How To Remix Old Paint

When it's time to clean up the basement, don't throw away those dusty old buckets of paint and primer. If the can was snugly closed and sealed, you can probably revive the paint for use on your next painting project. Old paint separates, however, so it must be thoroughly stirred up prior to use. You can request that service from your neighborhood paint retailer, or you can perform that chore yourself with some basic tools.

Most modern coatings are formulated with enough biocides and preservatives to produce a 10-year shelf life — under ideal conditions. However, if the paint was exposed to temperatures below 35 or above 100 degrees Fahrenheit, it is not trustworthy. If the stored paint was previously thinned with water or contaminated with dirt or rust, don't use it. If the paint smells like spoiled food when you remove the lid, it's time to dispose of it. Lastly, if the paint is no longer liquid, it's ready for disposal.

If your old paint can has never been opened or is nearly full, the retailer that originally sold you the paint is often willing to re-mix the paint at no charge using their high-performance blenders and shakers. Stores like Home Depot will use their paint shakers to shake your old paint for you. Just ensure the paint is sealed well and is not leaking. Also make sure to place it in a trash bag or plastic bin while you transport it, to ensure it doesn't spill in your car. When you take it home, the paint should perform like new with its color unaffected.

When the paint is only a few months old, it may show some separation, but you can blend it to optimal condition using the free stirring paddle supplied by your retailer. But paint that's been stored between six months to 10 years needs to be more thoroughly stirred up.

1. Clean the Lid and Rim

Lay the can on a dropcloth or some old newspaper. Wipe the top off the lid clean with a dry cloth and carefully scrape off any dried paint, rust or corrosion from the rim before opening. Use a a flat-blade screwdriver or paint key to open the lid.

2. Remove the Lid

Position the edge of a flat-blade screwdriver under the lid's rim and partially pry it up from the can. Repeat in three or more locations around the can's perimeter until the lid is free. Put the lid aside for later, making sure not to get paint everywhere.

3. Gently Stir the Paint

Vertically insert a wooden or plastic paint paddle into the can and gently stir the contents. If the paint fluids and color seem evenly dispersed, it's ready to use.

4. Power Stir the Paint

If your paint is really old, you will want to mount a paint mixing attachment to a variable-speed drill. Insert the attachment deep into the can and turn on the drill at low speed while slowly moving the mixing attachment around the perimeter of the can's bottom. Gradually increase the drill speed to medium, then turn off the drill after about a minute. After the drill has completely stopped, slowly remove the attachment from the can and allow any leftover material to drip back into the can.

5. Clean the Mixer and Replace the Lid

Clean the mixing attachment using the appropriate solvent: running water for latex paint or paint thinner for oil-based paint. If you don't plan to apply the paint immediately, replace the lid and gently hammer it into place with a rubber mallet.