Posted 03/29/2017 3:23 pm
I'm sure neither of us would be surprised if this was just environmental damage. It is unlikely that someone plated the coin, though stranger things have happened. Someone who knows more about the annealing process might be able to say with more certainty that this is or isn't something to do with that; but I have read that sometimes the copper in the alloy becomes relatively separated from the nickel, which may explain why it seems coppery to you in hand.
with John1. toning. Acetone will not hurt your coin. If it is a substance as mentioned it may remove it. What's up with the area on his temple?
