1891 Seated Dime. Cleaned?

This one's a toughie. Dipping alone does not cause hairlines and while it does not appear harshly cleaned in the images, it does display near-MS detail, AU+ for sure, so it's not like an obviously circulated coin that's got major issues. It has likely been chemically cleaned by dipping in an acid solution or by some other means. In spite of that, it might be deemed problem-free as an AU+ or low MS piece. Slight re-toning is evident on both surfaces which is good. I'd call it an AU55 or AU Details and Lightly Cleaned. Probably worth $50 to $70.

Looks wiped hard on the reverse. Very soft looking metal with lots of abrasions. I doubt it would grade problem free. Great die cracks on the reverse throughout the left wreath, definitely a later die state.

Looks cleaned to me. How harshly? Harsh enough that had it not been cleaned, it would look much different. Luster with toning.

Harshly cleaned in my opinion. Has made the surfaces almost look granular. AU-details.

I'd say you need go no farther than BH1964's opinion, although I'd put the coin's value at the lowest end of his estimate. Or, about half of retail for a "righteous" example.