Rare coins adorn the collections of professional antique dealers and ordinary lovers of antiquity. As with any object that has been influenced by time, copper coins need special attention and careful care. There are several ways to clean old copper coins.
- - laundry soap;
- - lemon acid;
- - acetic acid;
- - water;
- - brush;
- - terry towel.
Inspect the coin carefully before cleaning it. If it is covered with a uniform brownish film (patina), it may not need to be cleaned at all. Because this noble film not only gives the coin a special "retro" effect, but also protects the metal from accidental scratches and damage. Very often, after removing the patina, microscopic indentations form on the coin, which spoil its appearance and significantly reduce the cost.
A different approach is required for coins with a dark coating and oxide layers of a characteristic greenish color. If the contamination is negligible, it can be removed with warm soapy water. Rub a bar of laundry soap into a deep plastic bowl and fill it with hot water. Stir the solution thoroughly and let it brew. Place coins in a bowl and hold for a few minutes. Then gently brush off the plaque with a soft brush. Rinse the coins with running water and pat dry with a towel.
Citric acid is one of the most effective and safe substances that can remove dark plaque. At this time, the acid will react with the main plaque layer without damaging the metal. If the reaction is not strong enough, you can add a few teaspoons of acid directly to the solution. Then brush the coins with a soft bristle brush under running water and dry them thoroughly.
A more radical cleaning method is to soak copper coins in an acetic acid solution. For its preparation, you can use 70% acetic acid, which must be diluted to a vinegar concentration of no more than 20-25%. Or soak copper coins in a 9% vinegar solution. It is necessary to withstand coins in it, based on the degree of pollution - the more plaque, the longer it will take to remove it.