You'll find open arms for your computer more quickly if it has all its parts and it is working. Erase your personal files , but leave your programs. Take the software licenses and tape them to the case.
Keyboards get grungy.
Clean your old ones with a spray on-wipe off cleanser. Donate working VGA or SVGA color monitors. Inkjets and late model laser printers will be accepted. Software, packaged and sealed. Check for viruses please.