I'm new to this and I want to learn everything so I might have a few questions. Please be straight forward with me so I can learn it. Thank you.
Sorry, but it's dried glue or some type of resin. Whatever left that residue likely contributed to the uneven wear. It did not leave the mint like that
Thank you very much for your answer. I greatly appreciate it. Have a nice night
Since it's not a valuable coin, try soaking it in acetone based nail polish remover. Or buy yourself a pint of pure acetone as it's THE organic solvent for removing glue, gunk, grease, pvc residue, etc. Peace Roy