Got a handful of used bookstores in my area, and they get what I ditch. What they might not want usually goes in a box in front of one of the stores which acts as a freebie pile. There are a number of people in my apartment building that dump their old books on a table in the laundry room. I used to take some to the library but found that so many were getting stolen from there that I felt less motivated to go that route.