Cleaning copper-nickel coins
Copper-nickel coins are preserved quite well both in an aggressive environment and in soil. And since small change coins began to be minted from a copper-nickel alloy in Russia only in 1931, particularly old and heavily oxidized coins simply do not exist. But the main thing that happens to nickel coins is the coating with oxides of an unpleasant red-brown color. Such oxides are quite difficult to clean.
Cleaning Nickel Coins with Soap
A soap solution for copper-nickel coins perfectly removes green oxides (the same as when cleaning copper coins), but practically does not touch red oxides.
Cleaning Nickel Coins by Electrolysis
For copper-nickel coins, when cleaning them by electrolysis, there is one special limitation: if you use graphite or stainless steel as the anode (“+”), then the surface of the coin will be well cleaned of oxides, but due to the presence of copper in the coin’s composition, it will acquire a characteristic copper tint. To eliminate this drawback, you can either use a nickel anode or carry out cleaning in two stages: the first is cleaning with a conventional anode and the second is covering the coin with a layer of nickel (the same cleaning but with a nickel anode).
| This ruble was covered with unpleasant red-brown oxides as a result of lying in the ground for several years. Using electrolysis cleaning, all oxides were removed, but the coin acquired an unnatural copper tint. To remove it, the coin was coated with nickel, for which another coin made of the same copper-nickel alloy was used as an anode. |
This cleaning method is not universal and the only one. On the contrary, while showing good results for coins with weak damage to the coin field, for heavily oxidized coins electrolysis opens up all cavities and other defects.
| These 20 kopecks from 1945 were heavily coated with copper and nickel oxides. As a result of cleaning by electrolysis, all oxides were removed, but deep cavities were opened. In addition, the color of the coin remained dark. |
Vinegar, as an aggressive medium, can be used to dissolve oxides on the surface of the coin. The disadvantage of this method of cleaning is damage to the surface of the coin; the photographs show that the entire coin after vinegar becomes littered with small cavities. In addition, the color of the coin changes from an unnatural red-brown to an equally unnatural pink.
| This coin was cleaned with vinegar in which it spent about a day. After removing it from the vinegar, it was cleaned with baking soda and a short-bristled toothbrush. For comparison, it was photographed next to a coin that was stored in good conditions and has an ideal appearance and does not require cleaning. |
Cleaning copper-nickel coins in vinegar and salt
This is, so to speak, an attempt to improve on the previous cleaning method; the main disadvantage of cleaning in vinegar is the appearance of a faint, but still noticeable pink coating of copper on the coin.
Particular attention should be paid to the greenery on the coin; in areas of the copper-nickel coin on which there are dense green copper oxides, after such cleaning, pink copper spots will remain, which is not very beautiful.
Thus, this method is applicable in cases where the coin is coated with uniform red nickel oxides.
The essence of the technology is that we add a teaspoon of ordinary table salt to 50 grams of 7% table vinegar and stir a little.
It is difficult to dissolve such an amount of salt in such a small volume of vinegar, and this is not required; part of the salt should remain undissolved and lie at the bottom of the container in which cleaning is carried out.
During such cleaning, coins should not be placed on their edges, but simply placed on the salt and turned over every 2-5 minutes. Depending on the degree of oxidation of the coin, it will take from 5 to 20 minutes.
| Before cleaning, 20 kopecks of 1933 had dense green copper oxides on the surface, in place of which there were unattractive shiny pink copper spots. 15 kopecks of 1941 were cleaned in vinegar and salt, after cleaning the coin was ground in soda slurry. The cleaning time for each of the coins was approximately 20 minutes. |
Trilon-B is a fairly strong cleaning agent; it easily dissolves any oxides on the coin. And since copper-nickel coins do not have such a valuable patina as copper or silver coins, cleaning them with Trilon cannot harm them.
| 15 kopecks from 1953 were cleaned with Trilon-B solution. The coin was immersed in the solution for an hour, removed from the solution several times and rubbed with soda slurry. In order for both sides of the coin to be cleaned evenly, it is advisable to place the coin on its edge and lean it loosely against the wall of the container with the solution. |
Cleaning Soviet copper-nickel coins in hydrochloric acid (HCl)
Since it is quite problematic to buy pure hydrochloric acid in ordinary stores, for cleaning we used the “Toilet Duckling” plumbing cleaner, which contains the same hydrochloric acid.
| These 20 kopecks from 1931 were cleaned in a few hours in a solution of “Toilet Duckling” with water. The red coating was removed quite well, but in two places on the coin copper appeared at 8 o’clock and at 6 o’clock. Since the original color of the coin is gray or silver, the appearance of such pink copper shades does not look very nice. Also, a large number of shells and cavities opened up on the coin’s field, and part of the relief was also lost (before cleaning, even small details were clearly legible). |
In general, the abrasive cleaning method is not desirable and is completely unacceptable for rare and valuable coins, but can be used to add shine to inexpensive coins from modern or not very old circulation.
Such cleaning only has a negative effect on the value of the coins, so if the coins are ever sold, it is best not to clean them with GOI paste and other micro-abrasives.
As a result of such cleaning, small details are erased and for coins of average or poor preservation this method is not applicable since the relief can be completely destroyed.
| To clean this coin, we used GOI paste + a felt attachment on an engraver (Dremel 4000, speed 10 - 15 thousand per minute). In 2 minutes, the oxides were removed from the coin and the patina began to shine like new. The shine is certainly beautiful, but not at all natural for a coin that is several decades old. |
| The method of cleaning with GOI paste is most suitable for bimetallic coins, since problems may arise with chemical cleaning due to the dual composition, but such problems cannot arise with micro-abrasive cleaning. The photo shows the result of cleaning bimetallic 10 rubles; next to it for comparison is a coin in approximately the same condition, but not cleaned. |
Source: http://99-kopeek.ru/chistqa_monet/chistqa_niqelevyh_monet
Ways to clean coins at home
The issue of cleaning coins is most often a concern for collectors. Some believe that home conditions are not suitable for this; others claim that cleaning a product at home is no more difficult than washing dishes.
Cleaning iron and zinc coins
Soviet coins were often made of iron and zinc. Working with such material is not difficult. To work, you will need hydrochloric acid, previously diluted with water. The product is used for preliminary washing; the plaque is directly removed with a brush, the bristles of which are made of brass wire.
Rust can be removed with a knife; to get the usual shine, rub the product with a piece of dense fabric. When working with hydrochloric acid, it is important to maintain proportions. If you take too concentrated a composition, the old drawing will simply come off or be damaged. After treatment with a saline solution, it is imperative to rinse in soapy water and wipe dry with a soft cloth.
Lead, tin and aluminum
To clean lead, tin or aluminum coins, avoid using chemicals. If the dirt does not form huge stains, you can remove it using a glass brush.
In this case, the coins need to be rubbed well on cloth or felt. After cleaning, regardless of the metal used in the alloy, you need to thoroughly rinse the product, first with warm and then with cool water.
This will prevent recurrence of damage and the coin will look beautiful.
Silver cleaning
The silver version of coins is not difficult to care for. For work it is permissible to use: soda, a weak solution of sulfuric acid, citric acid, ammonia, Silbertauschbader.
Soda
If you decide to use soda, then first soak the coin in a weak vinegar solution or lemon juice solution. It takes 15-20 minutes to stand it. Next, mix baking soda with water until you get a paste.
Using your fingers, rub the pulp over each coin, tracking how the dirt goes away. This way of caring for your silver will not only get rid of impurities, but will also begin to shine beautifully.
This method is only suitable for non-valuable items in your collection, since the abrasiveness of soda leaves micro-scratches, which affects the final cost.
Sulfuric acid
If a bright green coating has formed on the surface, then for cleaning it is better to give preference to a low concentration sulfuric acid solution. To work, you will need a porcelain cup into which the coin is placed and filled with solution.
After preliminary softening of the plaque, remove the coin and remove dirt with a soft brush, rinsing with tap water. If the acid solution is preheated, the process will speed up.
Do not forget about safety precautions when working with acid solution.
Limonka
A solution of lemon juice of low concentration will serve a good purpose in the process of washing silver. The coin is placed in the solution and gradually turns over. When the dirt begins to peel off, rub the items with a soft cloth. If the dirt is not completely removed, use the procedure again. It is important not to leave the coin unattended for a long time. It may lose its natural color.
Ammonia
An even easier way to get rid of stains is ammonia. It does an excellent job of removing greens and other compound deposits. It takes no more than 60 seconds to hold the coin in it. Rub the coin with a cloth for about the same amount of time, which will remove deposits that are not naturally expected.
If a minute is not enough for cleaning, the procedure is repeated. If the oxides are still not removed from the coin, you cannot do without abrasive means, although numismatists do not recommend this method. Most collectors prefer Silbertauschbader.
However, it can be difficult to obtain, but you can order it online.
Nickel coins
The nickel version of coins gets rid of green oxides using a soap solution, but it will not cope with red ones. The most commonly used solution for cleaning nickel coins is acetic acid.
Since this product is an aggressive environment, the disadvantage of this cleaning method will be damage to the surface layer of the coin. Typically the result is a large number of small cavities.
However, compared to a red-brown coin, which looks completely unnatural, one cleaned with vinegar looks nicer.
To get the job done, just use table vinegar. The products are placed with tweezers for several minutes and washed with tap water. To remove pinkish stains, you can rub with salt. However, do not forget about the abrasiveness of the product, which means the appearance of small scratches.
To work, you will need 50 grams of table vinegar and a teaspoon of table salt.
The mixture is thoroughly mixed; the salt does not need to be completely dissolved. During this cleaning, coins are placed on salt, which will fall out as sediment, and are turned over every two to five minutes. Depending on how much the coins have oxidized, it will take up to 20 minutes.
Hydrochloric acid
You can use hydrochloric acid for nickel coins. However, buying it in its pure form is quite problematic, so numismatists working at home are advised to find a replacement for it by choosing a plumbing cleaner that contains hydrochloric acid. There are plenty of them on the household chemicals market. Coins are placed in the product for several minutes and washed well under running water. Don't forget to use gloves.
Paste GOI
GOI paste can help in the fight against complex stains. However, this method is undesirable, and as for rare and valuable items, it is completely unacceptable. However, inexpensive coins with its help acquire a chic shine. Therefore, this method is only suitable for products that you do not plan to sell.
The action of GOI paste is based on an abrasive composition. By and large, the same as in the process of cleaning with soda, but the composition is more professional, so cleaning is carried out much faster. If coins are poorly preserved and have small relief, which is important, abrasive methods should be abandoned, as you can completely lose it.
Source: https://ochistote.ru/chistka/metall/chistim-monetyi.html
Copper-nickel alloy: properties, GOST. Production of copper-nickel alloys. Cleaning Copper-Nickel Coins
Copper belongs to the group of non-ferrous metals. In its pure form, it has high thermal and electrical conductivity, which is why it is used mainly in electrical production. Copper is a very ductile material that lends itself well to pressure processing in cold and hot conditions.
To improve the mechanical, design and operational properties of copper, its compounds with other metals are used. As a result of the fusion process, the structure of the crystal lattices changes, and additional bonds arise between ions and atoms. This is what increases the strength of the alloy compared to pure metal.
Why is copper alloyed with nickel?
During fusion, nickel acts as the main alloying element. It is corrosion resistant and is therefore mainly used for strengthening. When it is fused with copper, continuous solid solutions are formed. The copper-nickel alloy acquires a number of new properties:
- the heat resistance of the material increases;
- the temperature coefficient of electrical resistance is significantly reduced;
- high resistance to corrosion appears, especially in sea water.
Classification
The properties of a copper-nickel alloy depend on the percentage of nickel and other substances in it. Currently, many new special materials with unique characteristics have been created. Depending on the area of application, they are divided into structural and electrical.
- Structural - have high anti-corrosion and strength characteristics. Products made from them are resistant to aggressive environments. These are cupronickel, nickel silver and kunial. A special place in this list is occupied by Monel, the composition of which and the proportional ratio of elements are somewhat different.
- Electrical - characterized by increased electrical resistance and thermoelectric properties, they are used in energy and electrical engineering. These are constantan, manganin and copel.
Knowledge of the chemical composition and physical characteristics allows us to determine the copper-nickel alloy into one of the groups.
Cupronickel
Contains approximately 80% copper, approximately 20% nickel, and some manganese and iron. A similar alloy was known to people back in the 3rd century BC. e. called "white copper" due to its light silvery color, reminiscent of silver.
This is a copper-nickel alloy with high anti-corrosion properties, as well as a large margin of strength and wear resistance. Melting point is approximately 1170 °C. Good ductility allows products made from it to be processed by pressure.
It is used in the production of capacitors; medical instruments, inexpensive jewelry, cutlery, and coins are made from it.
This is a copper-nickel alloy with the addition of zinc, having a silvery color with a greenish tint. Depending on the brand, it can contain up to 35% nickel and up to 45% zinc, the rest is copper. Such a significant zinc content significantly reduces the cost of its production. Nickel silver has approximately the same mechanical properties as cupronickel. It is resistant to corrosion, durable, and flexible enough to be processed hot and cold using the pressure method.
Sometimes it is additionally alloyed with lead for better machining. Parts of devices, watches, and medical instruments are mainly made from it. It is interesting that, thanks to its low cost, jewelry, medals and orders are now made from it more often than from cupronickel. Nickel silver is also used in the manufacture of enamel.
Kunial
It consists of a copper base, nickel - up to 20%, and small additions of aluminum. It is fused at a temperature of 1183°C, followed by hardening and aging, which achieves very high strength and resistance to low temperatures. It is divided into grades A (MNA13-3) and B (MNA 6-1.5).
Grade A has two important characteristics - high strength and unique resistance to corrosion in aggressive environments. For example, it can be used in sea water for decades. Therefore, the alloy is used for the manufacture of special-purpose parts (propellers).
Grade B has spring properties, therefore it is widely used for the manufacture of elastic elements for critical purposes. It is also very resistant to breaks in the cold. It is used to produce structural parts that operate at low temperatures.
Monel
It contains approximately two-thirds nickel and one-third copper. Melting point - 1350 °C. The main property of this copper-nickel alloy is corrosion resistance. It has high mechanical properties - strength and plastic deformation. Monel brand NMZhMts contains approximately 28% copper, 3% iron, about 3% magnesium, a small amount of cobalt and nickel.
Monel-400 has the same characteristics. It is a brand of Special Metals Corporation and was patented in 1906. Therefore, other manufacturing companies cannot use this name. This is how another alloy appeared - Nicorros. However, these materials are identical in all chemical and technical characteristics.
Since the alloy contains more than half of nickel as a percentage, its cost is quite high. However, there is a technology for the production of copper-nickel alloy using raw materials from natural sulfide ores containing both elements, without prior separation into individual components.
This allows you to significantly reduce the cost of the final product.
Monel is used for the production of products used in aggressive environments and conditions of increased mechanical load. These include shipbuilding, the chemical and oil industries, the production of medical instruments, critical machine parts and apparatus.
Constantan
It has a white color with a characteristic yellowish tint. The composition includes: copper -59%; nickel – 39-41%; manganese – 1-2%. Melting point 1260 °C. This copper-nickel alloy got its name due to its main property - thermal stability.
It has very good electrical resistance with a low temperature coefficient of expansion.
The alloy is used for the manufacture of wire for thermocouples, in the production of measuring instruments, as well as electric heating elements operating at temperatures up to 400-500 degrees.
Wire made from constantan is subjected to special heat treatment, as a result of which the metal forms a thin oxide film on the surface. Thanks to this, the product does not require additional varnishing or protective coating. Constantan is very flexible. This property allows it to be used when welding copper-nickel alloys.
The disadvantage of constantan is its rather high EMF - about 43 μV. This eliminates the use of wire and tape made from it in high-precision measuring instruments.
Manganin
Contains approximately 5% nickel, 12% manganese and a copper base. Melting point - 960 °C. Interestingly, manganin was invented by the American Edward Wenston around 1888 on the basis of constantan, which he also invented, as a special material for windings of electrical measuring instruments. It really has a high electrical resistivity, as well as an extremely low EMF when paired with copper (no more than 1 μV), which distinguishes it from constantan.
In order to reduce the temperature coefficient of resistance, manganese wire is annealed at temperatures of about 600 degrees under vacuum conditions, then slowly cooled.
This technology makes it possible to increase the temperature at which the material retains its electrical properties to 200°C. The wire already wound into coils is additionally heated repeatedly to 150 °C.
This achieves the effect of artificial aging, after which changes in the crystal structure of the metal are minimized.
The main area of application of manganin as a material with stable electrical resistance indicators is the manufacture of various high-precision instruments for measuring electric current indicators (current strength, voltage, power).
Kopel
Another special alloy. Contains copper, 43% nickel, some iron and manganese. Melting point 1290 °C. Due to the optimal ratio of consistently low resistivity and high thermal emf when paired with various metals, the alloy is used for the manufacture of wire for thermocouples and electrodes. The thermal power of the material increases in proportion to the operating temperature:
- at 100 degrees Celsius - 6.95V;
- at 600 - up to 49V.
Copel is very heat-resistant - it can withstand heating up to 600 degrees without affecting its basic properties and is resistant to corrosion.
Copel is used in thermocouples of sensors of devices for non-contact temperature measurement.
They use thermocouples with maximum thermoelectric power - with chromium, copper or iron. These elements are positive electrodes, and the copel is negative.
The Kopel-chromel thermocouple is used mainly in pyrometry for continuous temperature control in the range from 200 to 600 degrees in industrial and laboratory installations.
Melting process
In the production of copper-nickel alloys, relatively similar technologies are used. Cupronickel, nickel silver, kunial, constantan, manganin are first melted in induction furnaces under a layer of calcined charcoal. Addition of waste to the charge is allowed up to 80%.
The smelting process begins with copper and nickel. As they melt, waste is added in large pieces, then small pieces. Zinc is loaded last.
After the final melting of the charge, deoxidation is carried out with manganese and silicon (nickel silver), or silicon and manganese (constantan and cupronickel). After this, all slag is removed from the surface of the melt and more charcoal is added.
Heat the hot mass to a temperature of about 1300 °C; if necessary, add manganese chloride for refining.
The technology for preparing kunials is slightly different, since they contain aluminum. Before introducing aluminum into the melt, 0.1% manganese must be added for deoxidation. And after the aluminum is dissolved, the surface of the melt is sprinkled with flux. If this is not done, films are formed that make the melt unsuitable for pouring.
Chemical, physical and structural properties determine the intended use of various copper-nickel alloys. GOST 492–73, GOST 5063–73, GOST 5187–70, GOST 5220–78, GOST 17217–79, GOST 10155–75 are the main standards for their production.
Coinage
Around the end of the century before last, coins from a copper-nickel alloy began to be minted everywhere. Its composition varied greatly between mints. But basically it contained up to 30% nickel, a minor iron impurity and copper as a base.
Since the metal for ordinary coins must first of all be ductile, malleable, wear-resistant and inexpensive, the composition of the coin alloy was determined in a practical way. Subsequently, cupronickel became especially popular for making coins.
Modern Russian coins are made of various alloys. In particular, coins issued before 2009 consist entirely of cupronickel. Steel coins in denominations of one and five kopecks and copper five-ruble coins are covered with a thin layer of cupronickel. This material is called “bimetal”. Thus, the cost of producing metal money is increasingly reduced.
Alloys of copper and nickel are little susceptible to oxidation in air. Therefore, its signs can only be found on old coins, or those that have been in an aggressive environment for a long time. Expert treasure hunters and numismatists use various means to clean valuable coins - from folk recipes to advanced technologies.
Cleaning with soapy water only removes greenish copper oxides well. Olive oil, acetic acid, and Goya paste are also used. It must be borne in mind that these products can not only remove plaque, but also react with the alloy itself, causing harm to the coin.
The most effective, gentle and fastest way is to clean coins made of copper-nickel alloy using electrolysis.
Source: https://FB.ru/article/326145/medno-nikelevyiy-splav-svoystva-gost-proizvodstvo-medno-nikelevyih-splavov-chistka-monet-iz-medno-nikelevogo-splava
Cleaning copper-nickel coins of the USSR: methods and means
In the period from 1931 to approximately the sixties of the last century, coins were made from a copper-nickel alloy. Over time, such products become covered with a film of oxidation, turning from red to dark brown. Cleaning nickel coins will not help restore them to their original pristine appearance, since it always damages the surface to a certain extent, but it may well make them presentable.
Using soap
Cleaning copper and nickel coins at home is quite possible. For each method, follow some rules:
- The products must be cleaned before the procedure.
- During this process, do not allow your skin or body parts to come into direct contact with caustic substances.
- At the end of the procedure, wash the coins with soap and hot water.
How to clean USSR copper-nickel coins?
The simplest method involves the use of soap, which is mandatory in every home. It is not difficult to dilute the soap solution; the products are dipped into it. The alkaline environment destroys the oxide on the surface, then it is removed with a stiff brush under running hot water.
The disadvantage of this method is the low efficiency of the solution. Achieving the desired result may take a long time.
Electrolysis is not for everyone
Another method of cleaning USSR copper-nickel coins will require a power source, which could even be a phone charger. The coin must be attached to the cathode (negative), the source must output up to 12 watts. A solution with salt (one tablespoon) or soda (two tablespoons) is added, into which the part is lowered. The current is applied from several minutes to an hour, depending on the desired result and the degree of oxidation of the product.
It is important to know that this method should not be used on coins that have noticeable surface damage. The result is accompanied not only by getting rid of oxide, but also by the manifestation of all cavities and flaws.
With vinegar and salt
Simple cleaning with vinegar damages the coin, creating flaws on the surface, without completely ridding the item of oxide. If you add a seven percent solution of vinegar and a teaspoon of salt to fifty grams, the result of the procedure will improve.
The salt should not be stirred until completely dissolved: it is important to leave a small layer at the bottom. They place a coin on it and turn it over every few minutes. The procedure usually takes up to twenty minutes.
After cleaning, however, a pinkish tint may remain on the coin.
In hydrochloric acid hcl
The method cannot be implemented from start to finish at home. It is almost impossible to get hydrochloric acid in stores; it is found in rare cases in pharmacies. It is extremely unsafe to create a substance outside of laboratory conditions. Various cleaning products containing hydrochloric acid can come to the rescue, for example, Cilit Bang, Toilet Duck, SARMA and others.
Trilon-B for uniform oxidation
Trilon-B is a strong cleaning agent. In some cases, the product will damage the material, but with copper-nickel coins there is nothing to worry about. It is best to choose this cleaning method for cases of uniform oxidation coverage.
The substance can be dissolved in water in a ratio of one to ten. The solution effectively cleans the coin: the duration of the procedure depends on the degree of contamination and the desired result. After cleaning, wash the coin with soap and hot water.
GOI paste
The method significantly damages the surface of the products, like any cleaning with abrasives. If the coins are rare and are being cleaned for sale, cleaning with GOI paste is excluded: polishing removes a thin layer of the surface, erases small details and the products lose their value.
GOI paste is usually applied to a soft rag, sometimes moistened with gasoline. Before you start polishing, you need to wipe a layer of paste on an unnecessary surface or object so that large pieces disperse and do not scratch the part.
In general, there are plenty of ways to clean nickel coins at home. Depending on the degree of contamination, you can choose the appropriate one.
Source: https://DedAntikvar.com/numizmatika/kak-pochistit-medno-nikelevye-monety-sssr
Methods and rules for cleaning copper-nickel coins of the USSR
In Russia, or more precisely, in the territory of the former USSR, an alloy of copper and nickel was used to make coins from 1931 to 1935. This alloy is considered wear-resistant, but it also has one drawback - over time, a layer of red-brown oxide forms on the coins. It is quite difficult to clean coins from it, but at home you can prepare products that will make cleaning copper-nickel coins of the USSR much easier.
USSR copper-nickel coin
What should you not do?
It’s worth saying right away that using such a popular means of cleaning coins as soapy water will not bring results, since soap can only remove minor dirt, but not oxides.
Some numismatists use vinegar when cleaning copper-nickel alloy coins. Indeed, this product can dissolve oxides in a few hours, but there is also a negative aspect of this procedure - vinegar can damage the image and make it blurry. In addition, the alloy takes on a strange pink tint, which makes the coin less valuable from a numismatic point of view.
Table vinegar
It is known that oxides are effectively removed with hydrochloric acid. Its home analogue is the popular means for cleaning plumbing fixtures from rust - “Toilet duckling”, containing hydrochloric acid.
It is noted that if you hold a coin in this product, the oxides will be effectively removed, but after a few hours copper may appear on the surface of the metal, giving the coin a pink tint. If the specimen has a silvery-white tint, then such cleaning may ruin it.
In addition, the hydrochloric acid contained in the product can disrupt the relief of the coin.
To give inexpensive nickel coins a shine, GOI paste is used. But this product cannot be used to clean rare coins from the USSR period. Firstly, GOI paste contains abrasive particles that clean off not only patina, but also relief images. Secondly, this product gives the coin an unnatural shine, uncharacteristic of coins that were minted almost 100 years ago.
Cleaning methods
Before you start cleaning coins using a popular means, you should choose the least valuable copy that you wouldn’t mind ruining due to a failed experiment.
There are such methods for cleaning coins from the times of the USSR:
1) Electrolysis: the essence of this method is to supply current to a slightly salted aqueous solution (electrolyte). This method is also considered the most dangerous, since a person has to use an electrical appliance.
In addition, you must protect your hands and eyes while working. To clean coins by electrolysis, you should prepare a power supply with a voltage of up to 12 volts. Its plugs are cut off, the wires are divided into 2 parts, and the ends of the wire are cleared of insulation.
The copper wires are twisted and soldered to metal clamps.
After preparing the source of electric current, you can begin making the electrolyte: take 1 tablespoon of salt and stir it in half a liter of water. The solution is poured into a plastic container.
The power supply is turned on, but you need to make sure that the clamps do not touch, otherwise the power supply will break. The clamps are immersed in the electrolyte (one of the clamps will emit a hissing sound - this will be the “+” that must be attached to the coin).
Another clamp (minus) is attached to some metal object (a spoon will do). The coin can be treated in this way for up to four hours. The duration of cleaning depends on the degree of contamination.
After cleaning, it is recommended to gently clean the coin with a soft brush and soapy water.
2) Cleaning with Trilon-B: this product effectively dissolves patina, but only if it is used correctly. One part of Trilon-B is dissolved in ten parts of water. Then place a coin in this solution and watch how it cleanses. The duration of the procedure depends on the degree of contamination of the coin. At the end of the procedure, you need to rinse the coin with soap and water and walk over the coin with a soft brush.
3) There is one non-standard way to clean patina from coins from the USSR period. To clean, you will need cigarette ash and water. First, the coin is moistened with water, and then ash is applied to it. The resulting pulp is left on the coin for 20 minutes, after which the ashes are gently rubbed into the coin and then washed off with clean water.
The main purpose of cleaning coins is to give them an acceptable appearance. It is worth remembering that too effective reading can deprive the coin of the noble patina that gives the coin its value.
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Source: https://DedPodaril.com/numizmatika/chistka-medno-nikelevyh-monet-sssr.html
Cleaning bimetallic coins: 8 simple and non-standard methods
Collecting bimetallic products is an enjoyable hobby that, with the right approach, can become an excellent investment. But careless numismatists sometimes forget that careful care and storage are an important component of the collecting process. How to clean bimetallic coins without shortening their “life”? There are several accessible and safe methods, but first a couple of important points about the coins themselves.
What you need to know about bimetallic coins
Bimetals are interesting numismatic products in their own way, requiring a delicate approach to cleaning and careful handling in general.
Peculiarities
To ensure proper “care” and storage for bimetallic coins, you need to understand what they are. The essence of such products is the combination of two metal blanks. Such coins are minted in many countries. The first examples of bimetallic coins date back to the times of the Roman Empire. For a long time, no one remembered the bimetal, and they returned to the production of coins only in the 17th century.
Interesting fact! It is noteworthy that many Russian coins theoretically fall under the concept of “bimetallic”. The fact is that for the production of banknotes (which do not contain valuable metals), a bimetallic alloy is used - copper-nickel, as a rule.
But numismatists use the term “bimetallic” to mean something completely different: the use of two types of blanks, made of different metals, in one coin. Only in this case will banknotes be of interest to collectors.
True, not every bimetallic specimen can be highly rated. There are also products for which connoisseurs are willing to pay a lot. More often we are talking about specimens with distinctive features, for example, a manufacturing defect.
The most expensive coins are considered to be from the Roman Empire and American proof coins minted in the 17th century.
Cleaning technology
It is advisable to clean expensive and very valuable coins without contact. Any abrasive and friction harms them and leaves scratches. Usually the bimetal is soaked in low-acid solutions for a long period of time (soap solution, weak solution of soda or citric acid).
After cleaning, coins are washed in clean water and the moisture is gently collected from them with a cloth, without applying pressure (even if the coin is made of hard metal, an alloy of copper and nickel). The fact is that the fabric can leave noticeable micro-scratches on such coins.
Acidic solutions are very effective in removing dirt and stains. But they must be handled with extreme caution. Gold and silver items can easily withstand citric acid solution, vinegar, and household acidic cleaners.
As a rule, these compounds do their job without damaging the coins (even if they are left in the solution for a long time). But at the same time, gold and silver are very soft metals that can be easily scratched by applying pressure when rubbing with a regular cloth or even microfiber. And scratched coins are much cheaper.
Therefore, moisture is simply carefully collected from the bimetal made of gold and silver with a microfiber cloth, without applying pressure.
Copper and cupro-nickel coins do not tolerate acidic solutions very well. If such a product is kept in an acidic solution, the copper may enter into a chemical reaction, and an unnatural red color will appear. Even if the coin is made of white copper-nickel alloy (white color indicates low copper content), it may turn red. And this will have a catastrophic effect on its value: the coin will be considered damaged, since the chemical process is irreversible.
This does not mean that the acid composition cannot be used to clean copper-nickel coins, it simply cannot be left in such a solution for a long time (no longer than 10-30 seconds). Copper alloys are very dense and hard and are quite difficult to scratch. When cleaning, they can be handled less delicately.
Soap solution
This does not mean ordinary soap, but liquid soap, or alternatively, you can use dishwashing detergent. It is enough to dilute 15 ml of the product in 0.5 liters of boiled water and place specimens from the collection that require updating into a container with the resulting solution. Leave for 40-60 minutes. Then remove from the solution and wipe each coin dry with a flannel napkin. You don't need to exert much effort to avoid scratching the coin.
Ammonia solution
A simple and effective method for cleaning bimetallic coins, but the active agent should be used very carefully (the main thing is not to overexpose the product in ammonia). So, for the work process you will need a shallow saucer filled with an ammonia solution (10%). To clean a coin from “traces of time”, just hold it in the solution for 5-10 seconds.
Afterwards, carefully remove, rinse under running water and be sure to wipe the surface dry until shiny. If once is not enough, you can repeat the “soaking” procedure a couple of times (if necessary, you can increase the number of cleanings to three).
Lemon acid
A weak solution of citric acid is an excellent alternative to any detergent (but it is better to use a similar method for simple contaminants such as dust and dirt). To obtain an effective solution, it is enough to dissolve 4 g of powder in a partial glass (225 ml) of warm boiled water.
Coins are placed in the prepared solution for 20-30 seconds. It is not advisable to leave the coin for a longer period, as citric acid may react chemically with copper. All that remains is to take out the coin, rinse it under running water, and dry it with a soft natural cloth.
If necessary, the procedure can be repeated four times.
Soda solution
For 1 cup of boiling water, 1 teaspoon of regular baking soda is enough. Of course, you need to keep the coins longer than in citric acid (about 20 minutes). To enhance the effect, after soaking, you can delicately clean the surface of the coin with any household cleaning powder.
Non-standard cleaning methods
For those who are not satisfied with simple soaking or want to try out a non-standard method of cleaning bimetallic coins, any of the options presented below will suit their taste.
Toothpaste
Bimetal reacts well to any toothpastes; the main thing is to choose the right brush for cleaning coins: it should have thin and long bristles. For one coin, a pea-sized amount of paste is enough.
Before cleaning, it is advisable to immerse each coin in warm water for a couple of seconds. Then gently brush the surface with a brush and paste. Do not press hard, otherwise scratches may remain.
The “signal” to stop cleaning is the lightening of the surface of the banknote and the appearance of shine.
Formic alcohol
The mixture is considered a very effective tool for giving a coin a bright shine. Formic alcohol means a medicine represented by 1.4% formic acid combined with 70% ethanol.
So, place a coin in a container with the prepared solution for no more than 3-5 minutes. The final stage is thorough polishing with a soft natural cloth.
But one cannot help but note the fact that after such cleaning (as some numismatists say) the items quickly tarnish.
Coca Cola
It’s completely unconventional, but, as practice shows, it’s very effective, because the main “cleaning” element of Coca-Cola is citric acid. The technology for processing bimetallic products is similar to any of the methods described above: placing the products in a solution, then drying and polishing with a natural cloth. The only difference is the duration of the effect of the composition on the coins: for a high-quality result, a long soaking will be required (6-8 hours).
Electrolysis
An option for special aesthetes, experts in physical and chemical reactions and simply jacks of all trades. Recommendation: it is better to first try the method on ordinary coins, and only after that start cleaning collectible bimetals.
To work, you will need an old mobile phone charger or a universal charger, two clamps, a metal object (copper and brass will not work) and a deep glass/ceramic container filled with saline solution. A few words about how to cook the latter.
To do this, you will need regular table salt and boiled/distilled water. Ratio: 2.5 g of salt per 225 ml of water.
The clamps are fixed on the power supply, then attached - one to a coin, the second to a metal object. Both products are placed in a saline solution. Now you can safely connect the power supply. The liquid will immediately begin to become cloudy - this is a normal reaction: oxides and dirt enter the solution from the coin. After completing the procedure, the power supply is first disconnected, and the coins are thoroughly washed in hot water and polished with a cloth.
How to store it correctly?
As soon as a novice numismatist gets his first copy of a valuable coin, the first question that arises is: where to put it for storage? What usually comes to mind are banal and completely unsuitable options for such a task, such as a shoe box or a simple plastic box.
If we are talking about a serious hobby with the possibility of turning it into a long-term investment, it is better to immediately take care of purchasing high-quality “storage”. It will help prevent damage to coins during storage and preserve their appearance. For this purpose, specialists have created and tested special containers for storing any numismatic collections.
The most common options: an album for coins, holders (holders) made of cardboard with a transparent window, special tubes, tablets, etc. Of course, such products are additional expenses, but they pay off handsomely, because even with long-term storage, the collection of bimetallic coins will be perfectly preserved.
Source: https://xn--80aknalggeqsd.xn--p1ai/%D1%87%D0%B8%D1%81%D1%82%D0%BA%D0%B0-%D0%B1%D0%B8% D0%BC%D0%B5%D1%82%D0%B0%D0%BB%D0%BB%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D1% 85-%D0%BC%D0%BE%D0%BD%D0%B5%D1%82-8-%D0%BF%D1%80%D0%BE%D1%81%D1%82%D1%8B% D1%85-%D0%B8-%D0%BD%D0%B5%D1%81%D1%82%D0%B0%D0%BD%D0%B4%D0%B0%D1%80%D1%82% D0%BD%D1%8B%D1%85-%D0%BC%D0%B5%D1%82%D0%BE%D0%B4%D0%BE%D0%B2/
How to clean a cupronickel coin
Cupronickel is a silver-colored alloy of copper and nickel, which is used to produce various products. Most often used for making cutlery, dishes, coins and jewelry. It has pronounced anti-corrosion properties.
Products made from cupronickel have disadvantages, the main of which is darkening and stains resulting from prolonged use and exposure to external factors.
Many people wonder how to clean cupronickel? This can be done easily at home using certain tips.
Why does cupronickel darken?
There can be many reasons for the darkening of cupronickel; they depend on the type of product and storage conditions. It is worth highlighting the following main reasons for darkening in the case of dishes and cutlery:
- High humidity. Moisture is the main enemy of cupronickel, causing stains. You should only store dishes and cutlery in a dry place, wiping them after washing. To prevent stains from appearing, it is recommended to use a dry, soft cloth.
- Care. Nickel silver surfaces require special care, since microcracks can trap food and other substances, which significantly affect the brightness and appearance of the products.
Darkened cupronickel tableware
Coins darken over time due to many factors. Unlike cutlery, coins are not washed and are stored in a variety of conditions. Therefore, cleaning coins requires much more effort.
Coin cleaning is usually done by numismatists, since old Soviet cupronickel coins are very popular, but most of them are in terrible condition.
A similar situation is observed with jewelry: improper care and storage place cause a decrease in the attractiveness of jewelry. Cupronickel silver must be cleaned periodically to maintain the acceptable appearance of the jewelry.
Methods for cleaning cupronickel
Cleaning cupronickel silver from blackness at home can be done in several ways. The choice of method and product depends on the type of product and the degree of darkening. For cleaning, you can use cleaning products, abrasives or foil. Next, we’ll look at how to clean cupronickel and what you need to do it.
The result of cleaning cupronickel
Cleaning nickel silver items with foil
The use of foil can be combined with the use of soda and salt. It is necessary to place foil on the bottom of a pan or other similar vessel. Place the utensils on the foil and fill them with water so that it completely covers them. Using baking soda and salt will help get rid of stubborn dirt collected in micropores. You can add about three tablespoons of each substance.
Cleaning cupronickel using foil
Then you need to boil the water and keep it on the fire for about 20 minutes. High temperature will not affect the alloy of copper and nickel in any way, so there is no need to worry. After the required time has passed, the pan must be removed from the heat and left until it cools completely, without removing the utensils from the water.
After cooling, the cutlery can be removed from the water and rinsed under running water. It is very important to wipe the products dry with a dry towel. So that the evaporated moisture does not leave new stains.
Foil cleaning is a fairly effective solution and can also be used as part of a coin cleaning routine.
Using commercially produced cupronickel cleaners
The development of the chemical industry allows the use of special cleaning products made in the form of gels, solutions or powders. Such means are quite effective, allowing you to put in less effort and time than using folk remedies and methods.
The best way is to use liquid products and dry cloth. You can use special napkins pre-impregnated with the product in production. Abrasive cleaning powders are no less effective, but they can scratch the surface, so they are rarely used for cleaning cutlery.
Some products create a protective film on the metal surface. This film protects against repeated darkening and damage to products. Therefore, special gels are recommended to be used to restore the appearance of old cutlery.
Cleaning from darkening with vinegar and soda
Vinegar and baking soda are easy to find in any kitchen, so these products are primarily suitable for cleaning.
Soda is used in the form of a solution. For 1 liter of water you need to add 50 grams of baking soda. You can rub the devices with the resulting solution using a napkin, or rinse them in a container. After cleaning, the product must be rinsed in clean water and wiped dry.
Vinegar should be used in the same way. The solution is prepared by adding a teaspoon of vinegar to a glass of clean water.
Such products will not help cope with old dirt that has penetrated into the micropores of the alloy; however, it is perfect for periodically cleaning spoons. Its advantages are the simplicity and availability of cleaning products.
Preparing a decoction for cleaning cupronickel
At home, you can prepare decoctions based on various substances that can be used to clean cupronickel. Usually the base is eggshells, potatoes or garlic peels.
A decoction based on eggshells is quite an effective remedy that can correct even old stubborn stains. It is prepared by adding the shells of two eggs to one liter of boiling water. Cupronickel silver products should be immersed in boiling broth for several minutes. After this, they can be taken out and washed with running water.
A decoction of garlic peels is prepared in a similar way. The effectiveness of the product depends on the amount of husk. The duration of boiling spoons and forks depends on the degree and age of contamination.
Potato broth is the least effective, but is gentle on coatings. Therefore, it is recommended for use when cleaning products with gold or blackening.
The use of ammonia
A solution of ammonia is prepared by adding 2 tablespoons of alcohol to half a liter of water. Polishing cutlery with this solution can quickly remove old stains. You just need to wipe the forks or spoons with a sponge with the applied solution.
There are many other ways and methods for cleaning cupronickel, but the above are quite sufficient for quick and easy cleaning.
Tips for caring for nickel silver products
To ensure that cupronickel products do not have to be cleaned of significant contaminants that are difficult to clean, it is necessary to carry out preventive measures. Proper care and storage prevents the alloy from reacting with oxygen and water. It is this chemical reaction that causes darkening and staining.
Cupronickel should be stored in a dry place, protected from water and moisture.
After using the devices, they must be thoroughly washed using regular detergents. Additionally, you can use special gels to create a protective film. But you should absolutely not use products containing chlorine. It negatively affects the appearance of the metal, causing it to darken and lose its shine.
After thorough washing, cupronickel should be wiped dry. This will avoid stains and water reaction with the alloy. Proper care of cupronickel allows you to preserve its appearance for many years.
Source: https://moy-instrument.ru/masteru/kak-pochistit-monetu-iz-melhiora.html
How to Clean Copper-Nickel Coins
Copper-nickel Soviet coins, especially those dug out of the ground, are covered with a black or brownish-red coating. How to get rid of it without ruining the coins?
If the coin has only a dark patina and a minimum of rust, then it is better not to clean it, so as not to harm it.
Soap
A soap solution and long soaking will help remove dirt and get rid of darkening. Use laundry or baby soap. Coins must be kept in solution for 1-7 days or 2-3 months.
Vinegar and salt
Many people use a solution of 9% vinegar and table salt to clean coins made of an alloy of copper and nickel. Pour vinegar into a glass and add a spoonful of salt. Place the coin in for 10 minutes, the main thing is not to mix coins from different alloys. After that, take out the coin, wash it, and erase the remaining marks with a school eraser.
Unfortunately, after using vinegar or citric acid, red marks appear on the coin. They are removed by soaking in hydrogen peroxide. Also try iodine, cover a coin with it, then rinse it off.
The worst thing is that after using vinegar, shells appear on the coins, and this affects their value.
Black bread
On the forums it is advised to soak nickel coins in a jar with brown bread crumbs and water. The jar must be closed, the liquid in it ferments and cleans the coin.
Detergent Silit
At home, cleaning USSR copper-nickel coins with Silit detergent brings good results. Use a stove cleaner. Take a couple of drops and clean the coin with your fingers.
Ayran
The fermented milk product ayran helps in cleaning coins, although the method is quite long. You need to soak for 3-5 days, after which the ayran is replaced with a new one, the coin is rubbed with your fingers and the result is assessed. The advantage is that the copper does not come to the surface, i.e. no redness.
Special means
On the Internet you can buy special cleaning products for copper-nickel coins, for example Silbo. It is very easy to use; the coin is soaked for 3 minutes, then wiped with a napkin.
How to clean aluminum coins
You can also buy professional product Shine Coins “Steel and Nickel” for nickel coins.
As you can see, there are quite a few ways to clean USSR copper-nickel coins, but each of them has its own drawbacks. If the coin is quite rare and you do not know how to clean it, it is better to leave this task to professionals so as not to spoil it and devalue it.
By the way, cleaning coins can either increase or decrease their value, since some numismatists like shiny coins, while others like them covered with a patina, emphasizing their antiquity.
Source: http://monety.in.ua/chistka-monet/365-kak-chistit-medno-nikelevye-monety
How to clean cupronickel?
Cupronickel is a silver-colored alloy of copper and nickel, which is used to produce various products. Most often used for making cutlery, dishes, coins and jewelry. It has pronounced anti-corrosion properties.
Products made from cupronickel have disadvantages, the main of which is darkening and stains resulting from prolonged use and exposure to external factors.
Many people wonder how to clean cupronickel? This can be done easily at home using certain tips.
https://www.youtube.com/watch?v=3rqVlTiv-Qs
How to clean cupronickel?
Cleaning coins made of different metals
For beginners about cleaning coins. Experienced collectors themselves know how to clean coins, so our article is addressed to beginners. They rub the coins with sandpaper, rub them with GOI paste, boil them in oil, soak them in ammonia and polish them with a mixture of soda and toothpaste. Never do this! It is better not to clean at all than to ruin a rare coin through inept cleaning. We will tell you how to properly clean coins in our article.
We have already written about cleaning coins, but in this article we will talk about more detailed methods for cleaning coins by metal. As you know, coins are made from a variety of metals (and not only metals) and the approach to cleaning silver coins and zinc coins should be completely different.
Cleaning gold coins
Gold coins generally do not need cleaning. Gold does not corrode, and if there is dirt on the surface of the coin, it is usually enough to simply wash the coin with your hands in warm water and soap. In this case, you need to be careful, because...
gold is a soft metal and any careless handling (impact from a fall, scratching on an uneven surface or hard particles of fabric, etc.) can lead to irreparable damage, directly affecting the value of the coin.
Never attempt to clean or even wash proof gold coins with a polished surface.
Cleaning silver coins
Wax-proof silver coins in normal low condition can be cleaned with a mixture of ammonia and baking soda solution. Just make a bath and put a coin in there for 10 minutes.
Take it out, rub it gently with your fingers (preferably wearing rubber gloves), rinse, look at the result and return to the bath with the solution. Repeat this until you get the desired result. For any type of dry cleaning, be sure to continuously monitor the entire cleaning process.
So that there are no surprises in the form of coins corroded by chemicals, covered with stains or having lost their shine.
Cleaning Copper Coins
It is best to first hold copper coins for some (sometimes quite a long) time in a solution of laundry soap. To do this, grate the soap and pour boiling water over it. Hold until the soap swells completely and dissolves (you can rub and stir the solution with your hands). The consistency should be jelly.
Part of the solution is poured into the bath and a copper coin is immersed. Periodically you need to pull out the coin and rub it with your fingers to see the result of cleaning. Sometimes the process of cleaning copper coins in soap jelly takes several days.
The process is slow, but it gives good results and allows good control over the cleaning state.
Cleaning aluminum coins
Most often there is no point in cleaning aluminum coins. If it is a cheap ordinary coin, then it is easier to buy it in excellent condition and put it in the collection. If a rare and expensive aluminum coin needs cleaning, then cleaning will not help it in 95% of cases. Corrosion on aluminum is so insidious and unpredictable that it is almost impossible to get rid of it, and if you dissolved the source of corrosion with a chemical reagent, then at best there will be cavities and the overall appearance of the coin will be even worse than it was before cleaning.
Cleaning iron and clad iron coins
Source: http://snplanet.ru/coins/3-collection/1178-chistka-monet.html
