What to do with used guidebooks?

I have about a thousand guidebooks. That is a slight exaggeration, but I do have a lot of guidebooks. While I would love to keep them all–in case I ever go back to destination X and reuse them– but it is probably not a smart thing to do.

I tried to use my 2003 Costa Rica Lonely Planet guidebook during my second trip last year and let me tell you, it did not work. Most of the recommended restaurants, hotels and business were no longer there. While the important stuff – like national parks and such — remained unchanged, you might as well just go completely without a guidebook at that point.

What do you guys do with older, used guidebooks? I have sold a few on ebay, but I am thinking there might be a better place to sell old guidebooks and buy new ones. Anyone?