Take Inventory of Your Left Over Paint and Organize by Type
Sort through your leftover paint. There are two general categories of paint: water-based latex and oil-based/Alkyd paint. Water-based latex paints are not considered hazardous household wastes and can usually be dried-up or solidified, and where local governments allow, it can be placed out with the trash. Oil-based or Alkyd paints, as well as paint thinners and other paint solvents, are considered hazardous household waste and cannot be poured down drains or solidified and placed out with the trash.
After you’ve sorted through your leftover paint, begin opening each can and examine the contents. Both latex and oil-based paints generally have a 10- to 15-year shelf life, depending on how well it was sealed, on temperature fluctuations in the storage area and other factors. Paint that has been unopened has a greater chance of still being usable even after 10 years than a can of paint that has been opened in the past.
Don’t use a screwdriver to open paint cans. This can bend the lid and make it harder to close. Use a paint can opener.
Don’t worry if a “skin” has formed on the surface of the paint when you first open it — this is normal. Stir the contents of each can with a paint stirrer and brush the paint onto some newspaper or other disposable material. If the paint has clumps or has an overly thick texture, it is not usable. Organize again, by separating the usable paint from the non-usable paint. Set the non-usable paint aside for later disposal.
Try to Use Leftover Paint or Consider Donating
Rarely will you finish a paint project and not have leftover paint. Storing leftover paint properly will increase your chance of being able to reuse that paint at a later time for other paint projects. If you can’t find another use for the leftover paint, consider donating it to someone who can use it.
Before you begin your paint project, carefully measure the area to be painted (height x width = total sq. ft.) to more accurately estimate the quantity of paint you need to purchase. One gallon of paint will cover approximately 350 to 400-sq.-ft. To see how much paint you need for your project, check out the paint calculator tool.
Always store paint in a cool, dry location away from sunlight and temperature extremes. Wipe away any excess paint on the outside of the can. Place a piece of plastic wrap over the opening and then replace the lid, firmly sealing it with taps from a rubber mallet and then store the can upside down to prevent air from entering the container.
Dispose of Water-Based Latex Paint
Dispose of leftover water-based latex paint appropriately. While some local governments allow water-based latex paint to be thrown away in the trash once solidified, the paint has to be dried-out completely before disposing of it. Even if you have used all the paint from a can, always allow the empty containers to dry-out with the lid off before discarding. If there is a small amount of paint left in the can, you can let the paint dry by leaving it in a well-ventilated area until it hardens, stirring it once every few days. When setting out paint to dry-up, try filling partially empty cans with waste paint hardener, shredded newspaper or cat litter to aid in clumping up the leftover paint so that it dries up faster. Consider recycling metal and plastic paint cans to reduce landfill waste. Check with your local government to see if your city/town participates in a paint can recycling.
When leaving paint out to dry, be sure to keep it in an area away from children, pets, and open flames.
Dispose of Oil-Based Paint
Always check with your local authorities on how to properly dispose of leftover paint. You can also use the PaintCare Site Locator to find a place to drop-off your leftover paint: http://www.paintcare.org/drop-off-locations/
PaintCare Inc. is a non-profit 501(c)(3) organization established to represent paint manufacturers to plan and operate paint stewardship programs in the United States in those states that pass paint stewardship laws. Their main effort is to set up more places for people to take unwanted, leftover paint.
It is not recommended to leave out numerous cans of oil-based paint to dry out because of a build-up of fumes.
Never pour liquid paint into the trash or down drains.
That’s it! Now you know how to dispose of old paint properly.