Check the condition of the book before you consider donating it. Make sure it does not have damage from excess wear or water, or contain excessive writing, which impairs the usability to someone else. If the book has practice exercises, it is best if the answers are not written in the book.
Many online sites accept textbooks for donation. If you want to keep the charity directly in your community, consider contacting local community colleges and universities to see if they offer a program for donations. You can also check with high schools and libraries, which are frequently open to any donations that cut costs and help students. Many programs also send books to prisons or halfway houses.
Check the publishing date on your textbooks. In order to keep information current, textbooks should ideally be less than 10 years old, if the information in them is subject to change. Look online to see if there are newer editions, and avoid donating any books that are more than one edition behind the current one. This is especially true in fields where information is constantly changing, such as in medicine.
Keep a record of the value of the books you are donating, based on how much you paid for them originally. You can use these figures as a tax write-off when filing your yearly taxes. Obtain a receipt for documentation purposes.