ways to ditch books, particularly tech books?

I have a bunch of books that are unlikely to be appropriate for goodwill, but might have uses besides holding up uneven table legs or being recycled. Many of them are tech books, some slightly out of date, some historical relics (pdp-11 era, for example).

Anyone have suggestions for disposing of them? If not, I'll probably just tear the covers off the hardcovers and send them off to the great paper recycling bin in the sky on franey road.