Hydrogen peroxide, you can heat it up in a microwave and dump the coins in that come out nice it my take a few times to get them cleaned good, after that soke them in olive oil (I only soke IH'S in olive oil) wheats I just clean in hydrogen peroxide ...
Stick them in a potato for over night... I'm serious !! Just push them right directly into a potato. Push them in until covered, let sit overnight then rinse clean the next day.