Any guesses as to what's happened to this coin? is it PMD? because whatever it is it did a damn fine job of making this penny look like it has a "satin" finish much like the ones from the latter half of the 2000's.
Looked to be a fair amount of pitting/ corrosion along the collar and on the rim. Could have been knocked around in sand for a bit and gotten that softened look!
That's my doing. The coin is in a case surrounded by a foam donut that's probably making look alot worse than it is. The coin did come from circulation so I'm not sure how much to attribute to just circulation. But that's not a bad guess either, a sonic sanding machine could do this, but I still don't know. I will add that the area where the lettering is on the reverse and all around the shield there is less of that "frostyness"..... Actually, good call on checking out the edge, the edge of the coin displays the same frost, but squished like it was rolled. I'm going to guess that maybe the planchet was like this before it was minted? Anything else you can think of I can check to verify?
I'm no expert by any means but something I learned here is that generally if it is a mint error relating to the planchet that the rim will generally be "normal" looking. I've had several coins that I thought might be errors but the state of the rim verified they were PMD. I think that might be the case here. One quite similar to your query is this mushy looking nickel I posted about a while back. https://www.cointalk.com/threads/what-makes-a-nickel-mushy-like-this-one.337219/ I kept it because I like it and it feels special to me but know that it's not an error and that something funky happened to give it a weirdly uniform satin look. Because there's no corrosion I can't imagine it was in water for any period of but maybe in a beach parking lot lol.
Speaking of the sheild if you look at the top, the border around EPU you can see lots of very light very small scratches/ hit marks. Since it's more raised it got more direct contact to whatever material caused the satiny look. I'd say sand or something along those lines. That being said its always worth while to check Error-ref sections on planchet and strike errors to be sure!
Thanks for that! That coin has pretty much identical PMD, furthermore you specifically mention how uniform it is. That's exactly why I was fascinated by this one. It's numismatic sea glass!