Everything depends on the amount of accumulated sediment and its hardness.
There is no universal method, although similar methods of cleaning coins. Everything depends on the degree of accumulated sediment and corrosion on coins.
I will try to present my most common way of cleaning (I
hope you will understand, because I do not speak very well English - my apologies in advance).
Coins must be cleaned chemically and mechanically. The purpose of chemical treatment of a coin, is that it can reduce the strength of sediment, but is little (less) destroy the
patina (
patina unfortunately 100% can be saved).
Coins must be first boiled in a mild acetic acid at 5 minutes (6 -9%, vinegar for food, to add a salad). Then, the coins must be in the liquid than half hour, to two hours (depending on how intense the sediment on coins).
Then, the coins would be cooked in a solution of water and baking soda 5-10 minutes. Then they must exists in the liquid from one hour to two hours (all depends on the amount and strength of the sediment on them).
After that, mechanically cleaned, electric sander. At an electric grinder to be mounted only brush true soft brass (to the less damaging the
patina on the coin). Be sure to use safety goggles and
face mask because the dust is toxic.
Coins are treated mechanically, until, on them to create a thin layer of brass. So the coins seem like they are gold (do not worry, this layer protects brass,
patina, which is below). This
part of the cleaning the most challenging, because it is necessary a great experience, not to destroy the coins, (I advise you to learn mechanical treatment of the
poor coins).
After the mechanical treatment, coins are again cooked in a mild solution of baking soda and water for about 5 minutes. Then they must exists in the liquid for one hour (so with these coins have been cleaned existing thin layer of brass).
When the coins they are dry, they were then cleaned about 80%.
Then it must be 100% dry (it is necessary to remove all the moisture from them, you can use a hair dryer). After that, apply Vaseline on the coins with 10% sulfur (mixtures can be purchased at better pharmacies).
Good rubbed the coins, then wipe the rest of the cream. Then take your Dental
Supplies or tapering tree, and gently remove the few rest sediment on coins (because of the spread with vaseline remaining sediment can easily waste a coins).
