1988 1 cent Mint Mark Error ?

Log in or Sign up to hide this ad.

There is no Mint Mark.
Your Cent was Minted at the Philadelphia Mint.

 

Agreed with paddy. But if you are talking about the item above the date, it's a plating blister.

 

copper plated zinc cores (aka zincolns) are notorious for gas or whatever from teh zinc lifting and making blisters, bubbles, etc on the thin copper surface. Then it just gets worse over time ...