What could be causing this nonsense? The front of this 2004 D penny seems fine. Please excuse my ignorance, but this has caught my attention and I know nothing about it. I've never looked at my change this close. There's some crazy looking cents out there! This other one was in a little cardboard that said "1969 S MS 65 PROOF" I had to take it out to photograph it. This one had a purple and red shine too. Why is the back so much darker than the front? And I thank you for your patience with me. I'm trying to read up on this subject, but there's alot to learn. But I'll try not to annoy you guys too much.
Hum, Copper is easily, well it reacts to its environment different, chemical reactions change colors, moisture paper, ect, the zinc cent is copper plated, coated, just never know what they were exposed to.
The packaging and storage method, no doubt, is what caused the toning. I, myself, have many cents (from when I was a kid) that I put (unknowingly at the time) into acid laden manila envelopes. Years later there was some spectacular toning.......
Ok I get the point. Crazy colors are nothing special. But purple piss? Really? I've got alot to learn...
It's really just a chemical reaction...many things could cause that, not just... Often you will see toning on just 1 side...it depends on exposure/contact with an inappropriate surface or condition, over a certain (usually long) time period. You can slow/stop this process by putting your "valuable" coins in protective capsules, etc. Do not "clean" coins unless you want to remove any possible value to a collector (there are ways to "do" it, but you will need to learn how first). Continue to follow this site & you will learn a lot & gain valuable knowledge. And as @Islander80-83 indicated, those staples can easily scratch/damage a coin making it worthless, so be careful (another reason to use capsules). Happy hunting!