I'm not sure if this is a post mint error or not. I did run the penny under water with a mild detergent (probably the first wrong thing). The marks did not come off after this. Should I put the coin in acetone? The reason I haven't done that yet is that it doesn't look like something ON the surface. Any suggestions on how to clean this? Thanks...
I think it's an optical illusion on the surface of the fields. The coin is so dirty that the dirt is giving that appearace on the field they look like canals on Mars surface . I would say post mint dirt damage Jazzcons joe
I have no idea what that is, I agree with JC that it is probably just an old stain that has influenced oxidation or directly chemically reacted with the copper in some way and won't come off without damaging the surface. One shouldn't clean the coin with detergent and if you do use anything, DO NOT RUB THE COIN.
Any damage post mint would not be an error. You could not call it a 'post mint error' but rather 'post mint damage'.
