Most of these towers haven't been used since probably around 2000-ish. One old Toshiba laptop has Windows 95 on it. I've heard the only way to erase hard drives is to download a program made for that reason. I wouldn't have a clue how to hook these oldies up to my WiFi, plus my data plan is limited to 5 gigs a month.

I would love to donate them to someone who can recycle them, rather than paying to take them to the dump. If I take them to the dump (they don't go into the soil - a company picks them up and does I have no idea what with them) I still don't want old info on the hard drives. If I burn the units or take a sledgehammer to them to destroy the drives, I would still have to pay at the dump, and the things would be useless for recycling.

I don't know what to do. Suggestions, please!?

I pull out all my hard drives, then recycle the rest..
Some day I might sledge hammer the old drives, or use a mega strong magnet to mess up the information on them..
There should be computer recyclers around your area , that will take them without the drives, they dismantle them - metal, circuit boards etc.. if not new enough to rebuild.

It is pretty easy to open the case & take out the hard drive.

That is exactly what I did. I removed the hard drives and donated the rest to a computer shop that was willing to take them.

The old hard drives are taking up a lot less space than all the old towers.

Getting rid of OLD (CRT) monitors is a lot more difficult.