My HD has a bin up front that accepts old batteries.
Offer the tools here in the classifieds for shipping
OR
you can put 'em on CL free but the mouth breathers and flakes that come out of the woodwork for free stuff is more trouble than it's worth 99% of the time
Please don't just put them in the "garbage can." These are electric motors and have some value as scrap, even if it's not directly monetary to you. Ask a local steel yard or metal fab shop if you can put them in their scrap bin, ask a local electric motor rebuilder if they'll take them, or just carry them into your local scrapyard....they might even put them on the specialty scale (vs the drive-on) and give you a buck or two. You'd probably get more if you open 'em up and just sell the motor with the windings, etc. Unfortunately, *I would* just toss the plastic cases 'cause my city makes "recycling" too expensive and too difficult, but they probably have a # stamped in the case somewhere for recycling classification.
Also my local scrap yard will just take cordless tool batteries, but they only pay for auto batteries (a $10 GC at AZ or O'Reilly is a better deal, though, for the latter)