Let me start by saying, this a circulated coin which may make it difficult to determine whether it was caused by a contaminated die or just pmd. There are 2 areas in question on the obverse. There are plating blisters concentrated on face and in front of face, but hardly anywhere else on the coin. The other area is the bust which appears to be a piece of tape. I tried removing the spot on the bust to no avail. These lead me to believe it could have been a contaminated die.
I was saying, that grease, oil and/or dirt contaminants could have been on the obverse die face in the face area that caused the copper plating to bubble up. Here are photos of the high luster on edge.
It is because there is nothing original about the coin. Yes its been circulated and no that did not happen at the mint. It really is as simple as that.
It is always the same with you. If you can't see the envonmental damage on the coin then I can't help. Coins are not as complicated as you want to make them. Stains are damage. Black spots are sometimes carbon, in this case they are environmental damage. There is zero original luster on the coin. The toning is from being in a clothes washer. Should I go on?
As the name suggests, plating blisters are occur during the plating process, not the striking process. Plating blisters are generally caused by improper cleaning of the zinc blank or contamination in the plating bath. Whatever is going to cause blisters is already in place by the time the coin is struck. I can't say for certain based on your pics, but it looks like corrosion pitting. Notice how all of them are located in the area that's also stained. IMO, it looks like whatever caused the staining may have breached the plating, resulting in "zinc rot". It has nothing to do with a "contaminated die" (BTW. Material stuck to the die results in filled die errors. IMO, calling it a contaminated die just confuses the issue. Filled die would be the appropriate term) Regardless, plating blisters do not add value
The coin had environmental damage and looks like something else stained it as well. It's worth one cent.
Everything you see as 'different' or as a possible error is staining/surface damage/etc/etc. There are no errors on that cent, I'm sorry to say.
