How to Dispose of an Encyclopedia

1). Sell at garage sale. It may be something of a long shot, but host a garage sale and put your encyclopedia on display. You probably won't get a lot for the set, but anything is better than nothing. Plus, someone else voluntary takes responsibility for the encyclopedia.
2). List it online. Another option that could earn you some money for your encyclopedia is to list it online either with an auction site (like eBay) or a general listing site (like Craigslist). You can also list it on Freecycle, which will help you find someone in your area willing to take the encyclopedia off your hands for free.
3). Donate to local library. Contact your local library and see if they are willing to accept the encyclopedia. Even if they don't want it right away, most libraries will have donation periods where they do accept books they later either keep or resell.
4). Donate to local school. Schools may be interested in receiving your encyclopedia. Even if it can't be used directly in the classroom, a clever art teacher may be able to use it in a project.
5). Donate to charity. If you can find a designated 501(c)(3) charitable organization to accept your encyclopedia, you deduct its fair value from your income for federal tax purposes.
6). Abandon it. A last option is to simply abandon the encyclopedia in a conspicuous place where someone else who might want it is likely to find it. This method may not necessarily work, however, and you should check to see if the encyclopedia is actually claimed in a reasonable period of time. If not, you should take responsibility for it so it does not become litter or any other sort of nuisance.