An average of two gallons of household paint per person are sold in the United States every year.
Frequently, not all of that paint is used right away, so the cans pile up in basements and garages, and on average, people keep paint about 4.6 years before they decide to get rid of it.
The good news, paint manufacturers say, is that paint lasts for years if properly stored.
To ensure long life, a tight-fitting lid is of prime importance. "Once a drop of paint gets in the chime [lip of the can], it will never seal properly," says Ken Zacharias of the National Paint and Coatings Association.
Dried paint in the lip can make opening difficult and let in air. The strategy he recommends is to place a piece of plastic wrap over the mouth of the can, fit the lid securely on top, and then turn the can upside down. This assures a tight seal.
If there are dirt particles in paint that's been around for a while, pour the paint through a strainer of some kind (cheesecloth works). If that doesn't take care of the problem, you'll need to get rid of the paint.
But what's the proper way to dispose of leftover paint?
Because of its chemical content, solvent-based or alkyd paint should not be discarded with the regular trash. Leftover oil-based paints, paint thinners, turpentine, and the like should most often be turned over to household hazardous-waste programs.
Latex, or water-based paint, however, is not considered hazardous - not at the federal level, nor by most state or local authorities. (Check local rules to be sure, especially in California.)
"People just don't know that latex paint is not hazardous, especially when it's solidified," Mr. Zacharias says.
Landfills generally accept only solid wastes, since liquids can leach into the soil. Nonetheless, says Bob Cross of Minnesota Pollution Control Agency, some people deposit unused paint with their regular trash. Earthmovers crush the cans, spilling the paint, which, when buried in the ground, can remain in liquid form.
Although this isn't perceived as a major environmental risk, given landfill liners, the paint industry recommends drying leftover latex paint before discarding it.
To speed the process, the paint can be poured into a box or bag filled with absorbent material, such as shredded newspaper, sawdust, or cat-box filler.
What about old paint brushes? "I think the average consumer just puts aside his brush and lets it harden," says Bruce Roundy, president of Brush Saver Inc., which makes wet brush- and roller- storage products. "Once dry, the brush can go into any landfill."
The National Paint and Coatings Association stresses the importance of practicing source reduction. Estimate the amount you need, then buy only that amount.
If there's still paint left when the job's done, it can be stored for touch-up jobs or mixed with other latex paint of similar color for use as a primer. Before mixing, though, review the instructions on the can's label.
Another strategy is to donate or exchange your paint. In Washtenaw County, Mich., for example, the opera guild accepts white and off-white paint in good condition. A high school art department and a Graffiti Free Collaborative are among the other takers.
Paint exchanges or paint swaps, conducted in conjunction with regular household hazardous-waste collection events, are a growing option for communities trying to facilitate a money-free exchange of leftover paint. (An exchange organizing guide can be found at www.paintinfo.org/leftover-paint/guide.htm).
(c) Copyright 2000. The Christian Science Publishing Society