Latex paint is not a hazardous waste. It can be disposed of in the regular garbage once the paint is dry. Paint will air dry if the lid is left off the can. However, if there is a large quantity remaining in the can, air-drying will require a very long time. You can speed up the process by stirring in clean kitty litter. A product called "latex paint hardener" is available at hardware stores. The District also sells latex paint hardener ($2/bag; enough to harden one gallon). Contact us at 413-772-2438 (MA Relay for the hearing impaired: 711 or 1-800-439-2370 TTY/TDD) if you wish to buy paint hardener.
Do not bring latex paint to the Household Hazardous Waste Day or to the Super Sites. It will not be accepted.