Do you have cans of paint leftover from past projects, some of which has been sitting there for a long time? If you no longer want to paint anything Misty Mint Julep (or whatever your old shade might be), you might be wondering how to dispose of the paint cans and clear a spot on your shelves.
First, the good news is that paint, when properly stored indoors away from temperature extremes with the lid securely in place, lasts a long time. In fact, the average shelf life of latex paint is 10 years, and oil (or alkyd) paint remains usable for 15 years.
So, before you give old paint the heave-ho, pop the lid and take a whiff. If it just smells like paint, you're in good shape. If it smells rotten, then not so much, and you can part ways. Another way to tell if paint is still usable is whether there are dried chunks or layers at the bottom or on the sides of the can. Remove any skin that formed on top and give the paint a stir. Brush out a sample on something and see if the color's right and glides on smoothly.
If everything looks (and smells) good, then consider donating paint to an organization that can use it or resell it. Some options include schools, community theaters, shelters, or Habit for Humanity ReStore.
Most waste collection companies request that only solidified latex paint can be thrown into the garbage and taken to the landfill. If there's only a small amount of latex paint left in the can, remove the lid and let it air dry. Or, pour the paint out onto newspaper and let it dry. Throw the newspaper, dried paint, and paint can into the garbage for pickup.
For larger quantities of paint, add kitty litter or shredded newspaper to the paint, stir, and let it air dry inside the can. Throw the can and dried contents into the garbage for regular pickup. You also can purchase paint hardener, a product found at home improvement stores for a few dollars; add it to the paint (up to 2/3 of a gallon), allow it to harden, and throw it all in the trash.
Oil- and alkyd-base paints are considered hazardous waste. When disposed of improperly, they could harm sources of drinking water. So rather than throw oil- or alkyd-base paints in the regular garbage, call your local waste authority to find out how to dispose of oil-base paints. In most cases, you'll take the expired paints to a local hazardous waste drop-off site. Or leave it on the curb during your community's hazardous waste collection day.
To help latex and oil-base paints keep for many years to come, put plastic wrap across the top of the can opening and replace the lid, ensuring a tight seal with a few taps from a rubber mallet. Turn the paint can upside down to create a strong seal and store on a shelf where temperatures remain moderate and steady.