It looks like it is actively corroding. It may have an acidic or caustic agent eating away at the coin. You may want to rinse it in distilled water to help stop the progression and keep it away from any coin that are valuable so that they won't corrode.
ANA ID: 3203813 - CONECA ID: N-5637 Clean a coin that may be worth collecting? Please DON'T! When in doubt, leave it dirty!!






















