@goat@hellsite.site eBay or local classifieds?

The problem with books is that there are *so many of them* that if you donate them to a library or a thrift store, they are very likely to end up in the trash because they do not immediately look like something high-demand. Because they likely get far more books inbound than there is demand for them.

Of course if you can get a guarantee that they won't be trashed then it'd still be useful, but IME most places are not willing to make such guarantees for precisely this reason, and so it may be easier to give them (or sell them for a nominal fee to discourage resellers) to some place or person that you *know* has an actual interest in those specific books.

(Of course if you have a local hackerspace, computer club, etc. then they might be happy to take them on as well!)