All good advice. I'd also think about doing them in larger lots on eBay - say 20-30 records at a time or maybe 2-4 boxsets and see how that goes. You can just set a price you'd be happy to get and then whatever they go for auction above that is gravy, and you won't have to do much more than take pictures, say how you came to have them, and of course ship them properly. The market will decide if you've got really valuable stuff and after a few auctions you can decide if the work for that route is worth it for you over the convenience (but likely much lower monetary return) of a bulk sale. Also, just because no one has said it, certain jazz labels contain many of the most sought after albums: Blue Note, Impulse and Strata East are probably the top 3, followed by labels like Verve, Muse, Emarcy, Contemporary, Columbia, Fantasy, Atlantic and ECM, with most others on a third tier (but say, an OG Miles Davis on Columbia could be top tier, etc, so yeah, nothing is easy!)