Looks like zinc pest was also one problem of coins minted during WW2. https://www.cointalk.com/threads/zinc-coins-how-do-you-restore-clean-them.364375/ https:/

Looks like zinc pest was also one problem of coins minted during WW2. https://www.cointalk.com/threads/zinc-coins-how-do-you-restore-clean-them.364375/ https://www.cointalk.com/threads/zinc-coins-how-do-you-resto...