Old pennies stuck together with green rust like putty!?
I was going through a trunk of old coins and alot of the pennies are stuck together with a green putty like rust!!! What on earth is this its holding the pennies together quite well, I can pry a few apart but some are just stuck! I also found some mercury head dimes, steel pennies, and this unidentifiable coin with a eagle on the front and what looks like a statue of liberty on the back. Any ideas on the rust putty and what this mystery coin is?!