I have included photos for 3 different year cents. 1) Red 1976 cent 2) Red 1982 cent, and 3) 1984 cent with a halfway coating, I assume. Why are the two cents red? What is the film not entirely coating the 1984 cent? Also, on the 1984 cent the “8” on the date and some of the words in “Liberty” seem to indicate doubling. As always, everyone’s knowledge and help is appreciated! More to come!
That is probably paint. If you have the time to conduct a pointless experiment, you can soak the red coins in acetone. I suspect the paint will be removed. The 1984 cent is entirely plated. It looks like the coin reacted with something to create the discoloration. It may have been something slightly acidic, because of the pinkish tone. This appears to be die deterioration doubling which is caused by aged dies forcing the metal out towards the rims. It is common and does not add value to the coin.
You shouldn't clean a coin, especially a coin that has value greater than face. You can use acetone to remove loose dirt and organic matter from a coin, but be sure to rinse it with distilled water afterward.
