I tried to get my 57 yr old unemployed brother-in-law to sell used books on Ebay. Just with family members he had an instant inventory of approx 5000 books. With every book he would make instant profit as everyone was willing to donate all their books to him. He wasn't interested, is just willing to do nothing at this time. Ugh... lead a horse to water.....so the local charities hit paydirt from us when I started hauling in all those books. At least they said thanks :) So when you're ready to clean out the cellar, let me know hahahaha. P.S. I think my son-in-law is in competition with you to catch the most fish ever.
LOL, there is plenty of fish to go around.
Books are an odd thing. I have a few really old books like a Physics book from 1902. It's worth squat (less than $6). I have another book that is a 1960's psych text book and I saw it on ebay for $75. Both are still in my book case.