Theres a waterjet contraption called a waterpic i use and i think if it were used with coins it should be able to clean them without making any damage, you can set the strength and only using water should be good, start low and build it up till it cleans the face and not blasts the snot out of it
NO WAY!!! Congrats man! I'd have been screaming the whole way home too. After finding that I'd be hitting that place HARD. You earned it man. First gold coin? Only out west...You guys and your gold rush history make me sick.