I see you do not take encyclopedia sets. Is there any place who may want them?
You might try area retirement communties. Many of them have a library area and a limited budget with which to fill it. Another idea is to see if any local shelters could use them. Some of these have libraries as well, and have even smaller budgets! Every once in a while a local school could use them as well, especially if they are a private or parochial school.
As a last resort, you also might see if any local artists who work with found objects and/or books and see if they would have a use for them.
I hope that gives you some options. Thanks for your question.