What should I do with unwanted library materials?

My friend works for a library and she gave me two books on CD. I don't know how she got them, if they were on the rack of for sale items at the library, or what. But I'm done with them and I want to get rid of them. I figure I can't sell them because they're marked as library materials, and I can't return them to the library system because its far away/they may not want them back. Should I just give them to Goodwill or Salvation Army? What should I do?What should I do with unwanted library materials?
Yep, you can sell them.

On your Ebay auction, state that these were former library materials and still have stamps and markings.
burn itWhat should I do with unwanted library materials?
Find someone who does want them. You could try to sell them your self. Library materials should be marked "withdrawn" if they are truly gone from the system.
Turn them in at the nearest library. They will probably sell them. If asked, say someone gave them to you.What should I do with unwanted library materials?
make a barnes and noble acount and sell them
Since you know where the library is located, give them a call or send an Email with the details about the book - including the catalog number. Just a remote possibility that your friend checked it out under her name and it still shoes un-returned, and your friend may have to pay up the fines or price of a new copy.

If the library does not want it, then donate it to a local school ( I am assuming it is educational material). If this is not possible, then you have the right idea.