I have a friend who’s husband has tossed coins into a big jug for years and the jug got water in it and the coins are now corroded. They can’t roll them that way, so she asked me to post a question to find out ways to clean them. If anybody has a way to do this, please let me know! Thanks so much!
Tarnix should work. Also try dipping them in lemon juice. It cleans silver why not coins. Metal polish should also clean and polish the coins. Or go to a coin dealer and ask them what they do to clean their coins.