I’ve finally admitted that keeping that collection of 1999-edition textbooks on the shelf is doing no one any good.
Are old (back-edition) textbooks worthless? Should I just throw them in the trash, or is there a chance that they are still useful to someone?
I don’t want/need any money from them, it just pains me to throw out books. But, if I must, so be it!
donate to a library or organization for their used book fund raising sale. take to a thrift or used book store.
i find that the books i learned from are valuable even if dated. a diagram or chart that helped you understand something is a strong and quick reminder. going to another text to refresh yourself on a topic is slower and not as effective at jogging your memory.
i think people look for the texts they learned from for this purpose or as a life history thing (you discarded the books when you had no space and later in life you have space and want to find copies of those texts again).
You could try www.betterworldbooks.com
See if wherever you went to school at wants them for the department. At the Mechanical Engineering building at the University of Arkansas, they have a small library with almost every textbook they have used over the years in the various classes they have had. The old textbooks are neat and useful as hell for research.
Salvation Army. They take everything.
Before you donate them to a charity, check what their rules are on textbooks. There are some that specify that they don’t want any textbooks that are more than five years (or some other specific time period) old. Such charities have found that old textbooks just don’t get sold, regardless of how cheap they price them. They will have to throw the books in the garbage and pay for them to be hauled to the dump.
You can also check Ebay (completed auctions) to see if they have any market value. Regardless, I prefer to take stuff to Goodwill rather than send it straight to landfill. At least there’s a chance of it being reused; otherwise, it’s easier for them to throw the things away.
Amazon has a textbook trade-in program, but I’m not sure you’d get much for such old textbooks.
The answer is never to throw them in the trash. Paper products belong in the recycling.
Okay.
Among other things, I’ve sold textbooks online professionally.
95% of textbooks more than 6 years old won’t sell at any price.
The other 5 percent are books that are too obscure to get new editions issued.
Here’s your first thing to do:
Go to www.bookscouter.com
Type in the ISBN of each book. Any books with notable value will be noted, along with people you can sell them to, and reviews of those people.
That might make you money.
The next thing to do, with the remaining:
Go to www.betterworldbooks.com and run the ISBNs for your stash.
They probably won’t pay you for what you still have after the above, but they may accept some of your books as donations. They’ll pay the shipping.
Beyond that, put the rest of the books in your car and try dropping them off:
1- Goodwill
2- Salvation Army
3- Local ‘Friends of Library’ group
I just ran a booksale for our local library.
We threw away* all donated textbooks, unless they were from the last 3 years. They won’t sell, even at 50¢, and we need our limited space for things that will sell. So you could cut out the middleman by getting rid of them yourself.
*Recycled, actually. But they were discarded.
Your books may not be wanted in the first world, but even old textbooks are better than no textbooks in the developing world.
Someone might want them- depending what the texts are.
Check out these organisations to see if any of your books fit what they are looking for.
Not entirely true. I was gifted (actually had them dumped on me) 3 large boxes of old textbooks, most from the 60’s. Found they had little value and none of the charitible organizations wanted them. I dumped them in my recycling bin. That night my bin had not been emptied and had a note that complete hardbound books were not acceptable for recycling.
I called my garbage company and asked why. Only the pages of the books are recyclable, the paperboard covers are not. I spent a couple hours at my bandsaw cutting the books apart to separate the pages from the covers.
They have a stupid Flash website now that I can’t link to, but interestingly, textbooks are one of the things specifically on the list of things that they don’t accept.
I love buying old medical textbooks at book sales. Not that I’m a representative sample, of course.
I wonder if there is a charity out there that takes used textbooks for distribution in poor areas of the world. Maybe you can’t sell your old genetics textbook here because BIO 332 has upgraded to a new text and nobody wants to be “behind”, but it would probably be a wonderful gift for a curious student in a poor country. I’m doing some Googling but not having much luck.
They do if you just leave them on the loading dock. 
I know the OP specified textbooks from the 1990s, but I’ll add this comment anyway: If the textbook is really old, it gains value back. For example, I have a small collection of math and engineering textbooks from the 1800s. Those have value.
Also, not all books used in classrooms are officially textbooks. Some reference books (e.g., Black’s Law Dictionary and Stedman’s Medical Dictionary) can actually gain value. I recently sold a 1960’s-vintage law dictionary for more than the brand-new ones sell for.
Please don’t unload them in thrift stores, Salvation Army, or the public library for their annual book sale. Please. Don’t. Don’t do this.
My daughter spent hundreds on textbooks and they were sitting there, a big heavy box. I looked and found some places online, picked Cash4Books.net. I checked the IBN numbers and managed to unload them there (free shipping) for a fraction of their worth, but at least I got rid of them. I just wanted them OUT of here, and SOON. (Otherwise, I would have torn out the pages of each $100+ book, weeping, putting the pages in the recycling bin.)
sell them on Amazon for cheap. By putting in the effort at, effectively, a low wage you strike a blow against the greed of modern book publishers and help somebody (the buyer) out.
Sneak them into a dumpster at midnight. It’s really the only cost-effective way to get rid of the things. Every time a teacher retires at our school, we go through the same thing. They always have a ton of old textbooks in their room that are totally useless and that nobody on the planet wants.