Here's my tips for selling books to a used bookstore for more $, condensed. 1. Put them in a clean box. 2. Make sure there's no water, oil, sharp objects, or anything alive with the books. 3. Call the shop, ask if they BUY books? What type do they want? Do they pay cash or credit? Do you need an appt?
The first 2 items seem obvious & aren't. I've had glass, compasses, rodents, bugs, books stuck together etc. A clean rag run over the books it doesn't hurt either.
I had an sf/genre fiction shop. People brought me encyclopedias, parenting, cookbooks, etc. none of which I bought. It's a waste of everyone's time. I paid less for whatever I DID buy because I had to go thru so much stuffl to get what I wanted.
If you wouldn't buy it, you probably shouldn't offer it unless it's pretty special. A tattered S. King probably not, but an 1850 hardcover on Indians maybe
You'd be amazed at the trash bags, etc. that come into a bookstore & folks expect premium $ for their junk.