So Im new too collecting and Im guessing this is just corrosion bubbling up but thought Id check to be sure. Thanks for the info. Im enjoying learning something new everyday. And you guys full of useful information.
Some threads that may be of use/interest to the OP: Don't clean coins! Verdi-Care™ Experiment with Verdigone (tm) on copper cents Verdi-Gone effect on Indian Cents Coin Care Chemical