DYK over half the stuff brought to household hazardous waste events could just stay at home? We’re talking latex paint. Dry it out and it can go in your regular trash. (Stir cat litter into the paint until it thickens and won’t pour.) If you have just a little left, open the can and let the paint air dry.
Other options: give the paint to a community center, charity, or school. (Would they take my rotten melon and school bus yellow colors?). Or save it for later. Properly sealed and stored, latex paint can last up to 10 years.
FYI: Oil-based or spray paint don’t harden and should be taken to that hazardous waste event.