Cover and seal paint cans. To preserve paint for later use, clean around the lip of the can, as any buildup will prevent a perfect seal. Then cover the top of the can with plastic wrap before replacing the lid. “This prevents rust from seeping into the paint and makes the lid easier to pry off,” says Alison Keane, environmental counsel for the National Paint & Coatings Association. Next, place a piece of wood on top of the lid and “hammer it once hard in the center for a good seal,” says Carl Koebbe, division merchandising manager for Home Depot. Store the can upside down so “the thin paint layer that forms will be on the bottom of the can when you use it next,” says Koebbe.
Store cans inside the house. Keep the cans in a room not subject to freezing temperatures. “The garage is the worst place to store paint,” says Keane. “Latex contains up to 80 percent water―once it freezes, it’s ruined.”