I broke this proof cent out of its holder yesterday when I noticed this small spot on the reverse. It sort of looks like a stain on the shield just above the C in ONE CENT. Any ideas of what may have caused this, or what it might be?
Perhaps some residue from the rinse used to clean the planchets? There is another spot near the rim under the "N" in CENT as well.
It's anyone quess as to what causes these spots. The 2019 proof coins are plagued by them this year. The Mint is aware and a number of sets have been returned. However the Mint is making no effort to improve their quality control.
Just a guess, but it looks like a water spot like furryfrog mentioned. The 2019 West Point proof cent has the same two marks on the obverse, although they aren't round spot like yours. I hope someone can explain it so we can all learn.
Yep. lots of issues in this years set... But, sometimes it gives it some character, too. I believe the W cents have a couple scuffs around Lincoln's head... Ugly but a bit of insight to how the process works, I guess.
