Looks like the plastic to me
ICS MS67
There are a few variety sites to check. Ie Coppercoins, variety Vista, wexler files, coneca ...as for errors there can be anything - in theory -...
......mmkay... the image of the coin in question appears to have an improperly mixed planchet which has its surface copper toned to a medium brown....
Some sort of old adhesive
Looks like a stain to me. ...so, maybe a spot of dirty water...
Looks like copper spots to me.
VF30 green bean
PR MS67 or 68
MS63
It could be a slab issue.
75 gut feeling
Xf45
MS64 FBL
AU55 Details no cac
MS65 cac green
Those greens and hints of purple are nice toning for the cent.
PR MS66 DCAM
AU50 Green been
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