When you read as much as some of us do, you just don't have room to keep everything. What do you do with the rest?
I just simp;y take them back to the local library. :}
We have a great used book store here where I can get a few dollars for the books I take in and so can go buy more books!
When we lived in Oregon the library had a used book store where we could donate books and they were sold for 50 cents to a dollar to raise money for the library. I used to give them all my books.
I keep every books that I read even when they suck.
We have literally boxes and boxes of books all over the house. We are selling them. There's only so much clutter I can take :). I need room to walk ...
Donate to your local Friends of the LIbrary so that they can be sold and the funds used to help with library programming.
Donate them to a charity bookshop.