Verdigris is corrosive and grows on metal. It can effect pure and alloy forms of copper, brass, and bronze, including items that may have once been plated with silver or gold. The effected metal is compromised and over time becomes brittle. This is commonly seen on outdoor bronze statues.
Verdigris on coins is often referred to as Coin Cancer, because it eats into the coin surface and will grow and spread causing severe damage over time. It is also contagious and can infect other coins nearby. Coins stored in a damp environment will accelerate the spread. Coin Cancer will basically destroy your coins value.
If you have a coin like this, immediately separate it from other coins. Check to see if it is high value. If it is valuable, you can go to your local coin dealer to see if they can at least try to halt the process. If it is low value, THROW IT OUT before it infects other coins.
EXAMPLE OF COIN CANCER
1966 Australian 2 Cent Coin – Bronze (97% Copper, 2.5% Zinc, 0.5% Tin)
EXAMPLE OF BRONZE STATUE
