We've lived in our house for 18 years and accumulated a lot of partially full paint cans. You know, you finish painting the kids' bathroom and you save the remaining 1/4 gallon in case you need to do some touch up. Years later and probably newer coats later, you still have the paint. But how do you get rid of it?
Oil-based paint can be brought to Haz-Mat Days that many communities have but they don't take Latex paint because it's not a hazardous material. Most cities & towns won't let you just throw the paint cans in with your trash collection because inevitably they break open and suddenly there's a leak of sunflower yellow from the kids' bathroom up your street.
So what to do? I've heard absurd suggestions like use a paint roller to keep rolling a sheet of plywood until the paint is gone. I have over 10 gallons of paint, that will take forever, no. Another suggestion is to buy paint hardener at the paint store, mix it with the remaining paint in the can and wait for it to harden, then dispose. Better, but some of my paint cans are nearly full and that will be a mess.
Then my paint store guy gave me a tip that Kitty Litter will do basically the same thing as their high-priced hardener for a fraction of the cost. But what about the full paint cans? So I simply grabbed a 5 gallon plastic container (USG-type or buy one at the hardware store), filled the remains of 5 paint cans and mixed the kitty litter in stages as I added the paint. (BTW, I ran out of kitty litter during this process and substituted sawdust from my shop vac, worked great too.) Mix with a big stick, again after a week and let it dry for another week. You end up with a mixture that I can best describe as damp concrete mix. I scooped the mixture back into the paint cans after the two-week drying time, replaced the lids, and off to the trash.
The latex paint / kitty litter mixture is not hazardous, and there will be no paint trails spilling out of the trash truck on Monday. Problem solved, cheap and efficient. Good luck.