Agreed, that is the zinc core corroding and expanding and breaking through the copper plating on the surface. Just like rebar does inside concrete
Collecting since 1972. Learning from then on
"Tell me and I forget. Teach me and I remember. Involve me and I learn." - Benjamin Franklin
My Dansco 7070 type set coin count: 37/76




My Dansco 8140,8143-8147 Washington-Quarter Albums



