I've aquired most of my vintage coloring books off of ebay. One question I found myself asking a lot of sellers; "By mint, do you mean the coloring book(s) is complete and un-used, or the book grade: like it was printed yesterday?" Rarly did this question get an answer, and the auctions with no answer got no bid from me.
One seller who did answer, found out just how valuable it could be. She had a vintage Mighty Mouse complete and un-used, She had used the term "mint" in the auction, and wished she hadn't. Nevertheless, she went over the book "with a fine tooth comb" for me. I gave her things to look for to aid in her inspection. I bid $30 and was out-bid by the end of the auction.
Something told me to keep the auction on my watch-page and check out the feedback the winner left. Soon there appeared a neutral complaint. Buyer claimed that the book appeared to be "Trimmed". Since this coloring book was not printed in the US, it's production is unfamiliar to many. Dark grey card board printless back cover, cloth tape spine, and rough uneven page edges. Soon the buyer did a "feedback follow-up", and retracted his complaint. That's right buddy, she didn't wear a blind fold and oven-mits when she graded it. I later won a copy of said coloring book from another seller, for much less than my original bid($15).
Sadly when bidding on vintage coloring books you've never seen, you really can't ask; "Is the artwork any good?" I've got a few vintage coloring books with artwork so horrible, there is not much crayons can do for it.
Yeah, I'm scanner, but not on the vintage stuff. Don't want to damage the spines.