If the paint has dried and hardened, this can be safely disposed of with other household solid waste (waste haulers will not take liquids). Paint can be dried with sand, cat litter, sawdust, by leaving the paint can lid off, or by pouring the paint onto paper. The paint does not have to be hard, just not in a liquid form.
Large quantities of paint in usable condition could be donated to a local school or non-profit organization.
Matthew 25 Ministries (M25M) may accept your usable liquid latex paint. M25M reblends the usable liquid latex paint and helps low-budget nonprofits, schools and public facilities complete maintenance, rehab and upgrade projects at a low cost. M25M also sends the reblended latex paint to underdeveloped countries for their use. Please follow the below guidelines prior to dropping off and contact Matthew 25 with questions at 513-793-6256:
• Cans without original labels are not accepted
• No oil-bases or combustible paint accepted.
• No empty or nearly empty cans; should be at least 1/3 full
• No dried paint cans
• No deck stain
• Only original containers with labels-no make-shift bottles or cartons
• Latex paint should never have been frozen, if it has, it is unusable
ReUse Center also accepts latex paint for $2/gallon and sells the reblended paint at a discount.