I'm not very knowledgable about error coins, so I tried looking it up online but I couldn't find anything quite like it. If it's not some kind of gunk then my closest guess is maybe a die break? I tried to see if I could gently pry it off, but it didn't budge. In fact, I was afraid it might break off a piece of it and somehow damage the coin. The raised area is more subtle than it looks in the first photo. If it's gunk, is there anything you think might help remove it, or would that be a bad idea at this point? What do you think?
I don't believe it to be a die break. It looks like it happened after the minting process. My guess would be some type of solder or something. Not sure why it would be copper color though.
That's what gets me, too - the copper color. My mom added this coin to her collection from circulation, so I'm not sure what its history was. Any idea why someone would try to solder it, though? It's funny, but it never occurred to me to try that because I was convinced it was copper! If it does come off, though, then obviously it's not part of the coin. I'll have to see if I can find my acetone and try it out tomorrow... ETA: thank you both for your quick responses!
As there is no detail on the substance but there is under the substance should tell you its post mint
