Dispose safely. Latex paint is not hazardous and can be safely thrown away with your regular trash once it is solid. Simply leave the lid off and mix in sand, sawdust, or kitty litter to speed up the process. Once it is solid, place the can next to your trash with the lid off so your waste hauler can see that it is dry. As for other types of paint, solvents, and thinners, Leave them in tight-fitting jars or cans and have them picked up or delivered to a hazardous waste disposal site. Never pour thinners, solvents or paint down the drain. In Hamilton County, call 946-7766 for more information, or go to nkyhhw.org/ if you live in Northern Kentucky.
Donate. Consider donating leftovers to a local theater group, parks department, school, or organization, or take it to a community exchange. Matthew 25 Ministries, for example, MAY accept your usable liquid latex paint. They reblend the usable liquid latex paint and help low-budget nonprofits, schools, and public facilities complete maintenance, rehab and upgrade projects at a low cost. There are strict guidelines however. Call 936-7320 to learn more!
Lastly, reduce waste. If you have more than half a gallon left over, try to use it for another project. Try mixing several colors of similar paints together. And make sure cans are properly labeled for future use.