Would you please tell me if it is a lamination error; if so would it command a much high higher premium since it is a proof coin. Should I keep it in its case or open it and have it graded if I want to sell it? Thank you.
What do the rest of the coins and the reverse look like? It looks to me like moisture or the elements got to it at some point triggering corrosion?
Unfortunately, it's environmental damage/corrosion and significantly lowers the value of your proof set. Sorry
