Why?! If the idea is to remove the ink residue, an important history is removed. This is what is known as a ink chopmark. It just does not look right. I personally would have bought it without the acetone bath.
I see a couple more key dates in your latest round of pics... 1926 Denmark 2 ore (and in nice shape too) and 1927 (looks like that year, at least) Norway 1 ore.
Plus, there is some verdigris on the observe that's quite prominent and will likely have an effect on its market value.
True, and please @C-B-D don't go randomly acetone blasting foreign coins. Some types may have been treated with chemicals that will react and cause discoloration. I've seen this with some Scandinavian coins, which your group has plenty of.
Results on the Chinese dollars are in. I had them add the variety as well. Pretty happy! Dragon dollar XF chopmarked, Fatman dollar AU chopmarked.