Beginning collectors and the lucky ones, in whose hands were ancient copper pennies, rubles, money, fifty dollars, altynniks or hryvnias, looking at them, think: how to clean an old copper coin? And, as it turned out, their most common mistake is an attempt to restore the shine of the coin. And this greatly reduces its market value! Indeed, in the cleaning process, the main thing is not to overdo it and not deprive the coin of a noble patina, emphasizing its antiquity! Let's try to clean the coins at home and not damage our collection.
Things to remember for a beginner
Of course, it's better if your rarities are cleaned by a professional, but you can do this task yourself. To begin with, the numismatist needs to remember that the natural oxides on an ancient copper coin, which are dark brown and sometimes black, are called patina. You can't delete them! They not only add value to your rarity, but also protect it from the damaging effects of the environment. Consider the patina - if it is smooth, then just wash your coin with warm water andwipe with a soft cloth.
Citric acid will help clean coins
In cases where the oxide layer is uneven and thick, it must be removed. For this, several methods are used. To get started, you should learn how to clean copper coins with citric acid, which can be purchased at any supermarket.
- Dissolve three parts of acid in seven parts of water, thus obtaining a 30% solution.
- Dip a coin into it and wait no more than 15 minutes.
- As a result of a chemical reaction, purification will occur and the dirt will rise to the surface.
- Don't worry if the coin turns a pinkish tint as it changes in a few weeks.
- After acid restoration, the coin must be washed in water and soap containing alkali to stop the effect of acid on the metal.
Sometimes the cleaning process needs to be repeated for better results.
Can I use laundry soap?
Cleaning the collection can be done in another, safer way. Numismatists know very well how to clean copper coins with laundry soap. To do this, it is planed on a fine grater and a solution is prepared (ratio: 1 part of soap and 8 parts of water), stirring it thoroughly. Coins are placed in soapy water for two weeks. Periodically, water is put on fire and heated, not bringing to a boil. Dirt from the coins will begin to come off during this time, however, sometimes (especially if the oxide layer is thick) you have to apply additionalefforts to clean (for example, brush them with a soft toothbrush), but most often it is enough to wipe such a coin with a cloth.
By the way, using soap is the best way to restore old tsarist and Soviet coins issued before 1924. And more modern ones can be ruined by such cleaning!
How to clean copper coins from greenery and other stains
In order to rid the collection material of stains, it can be boiled over low heat in oil. A good result can be obtained using vaseline oil, as it has a rather high boiling point. Namely, it is required for successful cleaning.
Coins are kept in boiling oil for 10 minutes, do not forget to just cover the container with a lid to avoid soot. Then they are allowed to cool and washed with soap. Don't forget to dip the coin in ethyl alcohol for a few minutes to remove the grease. After this procedure, it can take its rightful place in your collection.
How to clean copper coins from oxidation
If the coin is covered with a dark cherry coating of cuprous oxide, then it can be removed by immersing the coin in a 15% ammonia solution (a 10% ammonium carbonate solution is used instead, which is less aggressive towards copper).
Dark green indicates the presence of copper carbonate. This plaque is removed with citric acid (and exactly how it was described above). A less aggressive way is consideredkeeping coins in kefir for 2-3 hours. Do not forget to periodically look at how the cleansing process is going on.
Sometimes there are also coins that are covered with a pale yellow coating of lead carbonate. This, as a rule, indicates that there is a lot of the mentioned metal in her alloy or that she has been lying with lead objects for a long time. Such plaque is well removed with a 10% solution of acetic acid.
What to do if rust appears on the coin
If you are worried about how to clean copper coins from rust, you will have to use a slow-acting reagent. This is Trilon B. The thicker the layer of rust, the longer the coin will have to lie in the reagent.
And some numismatists advise cleaning with Coca-Cola. This method, although it seems somewhat strange, is nevertheless very effective.
Dry coins after cleaning
After you have succeeded in cleaning copper coins from dirt and oxides, they need to be dried. To do this, it is best to use paper towels folded in several layers, and cover your cleaned antique with another towel on top. Use only soft ones for this - so you will not scratch the surface of the coin! By the way, you can completely dry it in a drying cabinet at a temperature of 100 ° C. And in order to prevent and slow down the oxidation process, periodically rub the collection material with a crumpled newspaper.
What if a copper coinlost its noble patina?
If you still overdid it or for some reason you had to completely clean the coin, you can restore the patina layer by artificially aging the product. True, cleaned coins themselves acquire a patina over time, but it can look uneven and this greatly spoils the appearance of the collection material. In order to avoid this, the coin is degreased and dipped for 15 seconds in a 10% hyposulfite solution, and after drying it is wiped with a soft cloth. The described operation will help to create an even and beautiful patina on the antique.
Helpful tips
If you still don’t know how to clean copper coins in practice, then you should practice on less valuable items and only then move on to the most expensive items in your collection. In the case when the coin has become unnaturally light as a result of cleaning, put it on a sunny windowsill, where it will take on its normal appearance in a week. True, you must not forget to turn it over regularly.
If you come across a coin affected by the so-called "bronze disease", then it is better to give it to a professional restorer. You can distinguish this by oxides on its surface, similar to light green grains. And the coin itself, as a rule, is badly destroyed and crumbles if you pick it up.
A final word
We hope that after reading the question of how to clean copper coins at home, it will not seem too difficult for you. But still wantwarn that especially expensive and rare specimens of your collection should be given into the hands of a specialist. Otherwise, it may turn out that your rarity is hopelessly ruined.
By the way, toothpowder, paste, s alt, baking soda and sand are substances that can cause irreparable damage to the appearance of collectible material. After all, all these are abrasive substances that can scratch the surface of the coin and, accordingly, reduce its value.
Good luck with your restoration and collecting!
