If a coin is rare or a rarity, it is better to give it to the master for processing. But you can also try to clean it at home. Although it should be noted, if the coating on the coin is flat, and the metal has not touched corrosion, then it is not worth fighting with the patina. After all, it protects the metal from the effects of the environment.
But nevertheless it is necessary to know some ways of cleaning patina from a coin - it will suddenly be needed. After all, if you are a true numismatist, knowing how to properly clean copper coins will help you maintain your growing collection in perfect order.
Gentle cleaning methods
The most sparing type of cleaning copper is distilled water. The coin needs to be immersed for a couple of days in the water, where it may be covered with green flakes. They must be cleaned with a wooden toothpick or a toothbrush with a soft natural nap.
A slightly more aggressive form of treatment is ammonia. To do this, the coin is wiped with a cotton swab dipped in a solution of ammonia, and then washed in soapy water.
Boil in oil, too, you can. Just to begin with, make sure that there is no tin and other low-melting metals in the thing.
Active cleaning
A more severe type of cleaning copper coin can be considered the use of the following mixture: oxalic acid - 1 g, ethyl alcohol - 5 ml, turpentine - 4 ml and water - 1 ml. This solution should be shaken and applied with a rag to the surface to be cleaned.
And how to clean old copper coins? After all, they must be treated with care, so as not to damage. Since ancient times the recipe - "acetic flour" is known. For its preparation, only two ingredients are needed: flour and table vinegar. The dough is made immediately before cleaning. Then it is applied to the median and allowed to dry. Then brush off with a brush or a rag.
And as a "softener" of contaminants, sodium hexametaphosphate can be used. It is a salt that needs to be dissolved slowly and stirring, since its vitreous consistency sticks to the vessel. In the cold form it is not so active, therefore, to achieve the best result, it needs to be heated to 60-80 degrees.
Aggressive cleaners
What else can you clean the coins ? Use Trilon-B. But it must be used very carefully, because after cleaning, instead of a copper-nickel coin, a pink copper with deep caverns can appear. Trilon-B is suitable only if you have a purely copper copy.