t’s rare that you will finish a paint project and find you have used exactly the amount of paint you needed for the job. Leftover paint shouldn’t be discarded because you never know when it might come in handy for touch–ups or other unrelated projects, never mind that throwing it away wastes money. However, you need to store leftover paint properly so that it is reusable.
A lot of prep work goes into starting a paint project. The job isn’t over when you’ve applied the last coat. You need to clean up your work area and put things away before you can relax and enjoy your handiwork. Put as much effort and care into cleaning up after painting as you would in preparing for the project.
Start by picking up drop cloths and tarps. Pick them up carefully, making sure you don’t spread around any paint that may have gotten on them. Clean paintbrushes and other tools with warm, soapy water. You can also use a non-toxic, citrus-based cleaner for additional help. Thoroughly rinse your roller covers and brushes in water until the water runs clear, then place them in a brush/roller spinner, if you have one, to remove excess liquid. Store in their protective sleeves or hang them on nails or hooks.
Remove painter’s tape at a 45-degree angle to avoid removing any fresh paint. Remember that the longer it stays on, the harder it is to remove.
Dispose of used paint cans appropriately. Many people don’t know that leftover latex paint has to dry completely before you can dispose of it. Even if you have used all the paint from a can, allow the empty container to dry with the lid off before discarding. If there is less than a quarter of the can left, you can let the paint dry by leaving it in a well-ventilated area until it hardens, stirring it once every few days.
When leaving paint out to dry, be sure to keep it in an area that’s away from children, pets and open flames.
Only buy what you need for the job at hand so you don’t have too much extra paint. Before you begin, measure the area carefully (height x width = total sq. ft.). One gallon of paint will cover approximately 350 to 400-sq.-ft. To see how much paint you’ll need, check out the paint calculator tool.
When setting out paint to dry up, try filling partially empty cans with shredded newspaper or a powder to aid in clumping up the leftover paint so that it dries up faster for discarding.
There is no need to waste paint. You can save any leftover paint for touch-up jobs or use it to paint a small area of your home in an unrelated project. Always store paint in a cool, dry location away from sunlight and where the temperature stays above freezing. Before storing, 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.
If you don’t have the storage area to house leftover paint or don’t want the clutter, consider donating leftover paint to someone who can use it, like an artist or a theater group trying to stretch its financial resources.
If you have young children, it’s a good idea to purchase a lockable storage cabinet for all paints, chemicals and solvents.
Label the paint can with the color and location of where you used it for convenient reference later on.
Don’t use a screwdriver to open paint cans. This can bend the lid and make it harder to close later on. Use a paint can opener.
Don’t put liquid paint in the trash or pour it down drains to discard it.
The King County website has a page with information on proper latex, stain and oil paint disposal.