A little background first. I don't really consider myself a collector. My first child (son) was born in October, and I decided to get a couple 2008 coin sets to give him 100 years from now to say..."here these were from the year you were born! One of the sets was the 2008 Presidential $1 Proof Set. As soon as I opened the package I noticed the mark on the rim of the obverse of the coin. It almost looks like a burn mark. It is not part of the packaging. Please excuse the dust on the face of the packaging in the pic. Any ideas?
These coins commonly get spots like that due to the metal content. It may well develop more spots as time goes on. If you go these sets recently you may still be able to return them for new sets. But if it has been more than a month you are probably out of luck. That said, the sets must be stored properly or they will almost certainly develop more spots. Just do a search for "storage" and will find countless threads on the subject.
