Where can I get rid of several broken Roomba floor cleaning robots?

I have several used non-working iRobot Roomba floor cleaning units with chargers, extra brushes, extra accessories. I hate to toss in trash. Is there a place to give them away? Should I try to sell on Ebay or such? There are good parts, components, etc that someone should be able to use, but I have no clue on how to find these folks.