I'm rethinking my collecting again and have always loved the seated coins, thanks mostly to the 1853 with rays. So I've been doing some browsing on these Seated coins and came across this one. This coin has been graded and I do not own it but after looking at it, I don't know if I agree with the grade, what do you think it grades as?
I sure don't see any signs of corrosion so that may simply be a label mistake. But personally I would grade the coin as AU because of wear and a lack of luster. The lack of luster may be the real reason for the details grade, assuming it is a label mistake.
I'm seeing an MS details coin with something removed from the reverse. The holder appears to agree with this interpretation and it looks like the coin was lightly corroded (perhaps by a rubber band) along a diagonal on the reverse from the TR of TRUST through the wing and ending at the last A in AMERICA. Additionally, the GO of GOD shows possible issues, too.
That's what I was seeing as well. I was kind of thinking some type of adhesive that was stuck on the coin and removed since the area had a bit of a "rough" look that reminded me of tape.
Looks like ordinary toning that has been partially removed by dipping to me. As for what Tom sees, I looked at it, but it just looks like contact marks to me, not really corrosion. And the slight discoloration in the area could easily be from more toning that was removed. But anything's possible.