I’m a little intrigued by the reverse of this ‘54D and wanting opinions on it. Is this chemical damage? PMD? Wear and tear? Abuse? Something else? All of the above? Many thanks.
As a kid, I found an old letter in a trunk in the woods. It was for a sweepstakes where they attached a lucky penny (with glue). The coin was toned but the area with the glue protected. Looked a bit like that.
Agree with glue and possibly paper stuck on there too. Drop it in acetone, it might help. And it can't hurt.