Please use our links: LEGO.com • Amazon
Brickset.com is a participant in the Amazon Services LLC Associates Program, the Amazon.com.ca, Inc. Associates Program and the Amazon EU Associates Programme, which are affiliate advertising programs designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.
As an Amazon Associate we earn from qualifying purchases.
If they're valuable sets (i.e., exclusives, long retired Star Wars, etc.), then you'll probably get the most through individual eBay auctions (with all the attendant risk of selling through eBay).
LEGO appears to move pretty quickly on Facebook Marketplace, but you're limited to a local audience or have to deal with some of the same risks as eBay and shipping. I scoff at high prices on Craigslist and NextDoor, but have seen quite a bit listed there.
You can also try to sell the items in the marketplace forum.
I've bought full collections through estate sales. If you contact an estate sale/downsizing company, they do most of that work for you, but then also take a larger chunk of the sales price.
I have never sold through Ebay (or anywhere). I just listed a few items that are high value but with box damage and lowered the suggested starting bid quite a lot to account for the damage and included pictures of damage and noted damage in description. However, I am nervous about risk, as you mention.
I've determined it's largely up to your specific market, but apps like OfferUp and Mercari might be good alternatives too. My local OfferUp market seems to support fast sales of any vintage set that is not drastically overpriced. If there is a lot of activity on those sites in your area, they may be worth checking out.
I certainly wish you the best as you move through things. Don't forget to save a few of your favorites...just in case!