Most painting projects leave you with a small amount of leftover paint. The best idea is to use it—maybe for a second coat or a small-scale project like an accent table. If you can't find a use for it, properly dispose of latex paint by mixing the last bit in the can with kitty litter or paper scraps. Leave the lid off until the paint dries, then throw out the can with the trash. Take leftover oil-based paint to a hazardous waste facility.