[W] to the CCF!
If you can, measure the diameter of the coin. If it's larger than 19.01 mm it could be a "Texas Cent." If it's the normal diameter, it's most likely environmental damage as noted above.
ANA ID: 3203813 - CONECA ID: N-5637 Clean a coin that may be worth collecting? Please DON'T! When in doubt, leave it dirty!!
