Looks like a nice greaser to me https://www.error-ref.com/struck-through-smooth-viscous-material-grease-oil/
that's what I was looking for but couldn't remember. The discoloration too such as OPs example. I was also thinking .. maybe it's a zincoln eating itself. lol
From late 1982 the composition became a zinc core coated with a micro thin layer of copper weighing 2.5g
In 1982 due to the rising cost of copper we switched from coins being %95 copper and %5 Zinc to basically %95 Zinc and a little bit of copper aka zilincolns because there terrible!!!!
If its that much then yes most likely copper but can you get a closer picture of the Date?It just looks zinc to me,it could be a thick planchet or the 1 in a million of possibly a 82-83 Transitional copper.
And IGWT. It is no doubt zinc with the platig blisters. Nice grease filled die @Mary Neely OBv and Rev.