No matter how carefully you measure before you start a paint job, you inevitably end up with some leftover paint. In fact, according to Paintcare.org, a recycling organization, about 10% of paint purchased each year (70 million gallons!) goes unused every year.
I know that I have several cans waiting to be disposed of, but if you can’t just chuck it in the trash or pour it down the drain what exactly are you supposed to do with it?
First, determine if your paint is still good. If it is, you can donate it to a neighbor or Habitat for Humanity. If sealed correctly, water-based paint (like latex or acrylic) can last 5 years, and oil based paint can last 10 years. Open all the cans sitting on your shelf (or is this only me?) and if they have a lumpy texture and unpleasant smell you know they are bad.
If they are bad, you need to get rid of them, but you can’t just toss them away.
For latex and acrylic paint: Place them outside or in a well-ventilated area to allow paint to harden. This process can take anywhere from a few days to a few weeks. If you are interested in hurrying things along, add with paint hardener or kitty litter. After hard, remove the paint and put it in the trash and recycle the now empty can.
For Oil-based Paints: These are designated (along with enamels and varnishes) as hazardous waste and therefore have strict disposal requirements. These should never be left to dry because they can emit harmful fumes. Instead, find a hazardous waste disposal center near you through Earth911 or clicking here.