Closing the can so it keeps
Sherwin-Williams says to wipe the rim clean, lay a piece of plastic wrap over the opening, then seat the lid with a rubber mallet. Write the month and year you opened it on the lid.
Don't pour leftovers into jars or food containers. EPA says to keep hazardous products in their original containers with the labels on, and the U.S. Fire Administration says never to store oil-based paint or solvents in breakable glass. If you'll want an exact touch-up later, snap a photo of the label with the color formula and sheen, since two cans with the same color name can still differ.
Where to keep it
- Garage: Sherwin-Williams calls it one of the worst spots, because paint freezes in winter and cooks in summer. An unheated Philadelphia garage or shed freezes in January.
- Basement, closet or utility room: these are the places Sherwin-Williams recommends. In a basement, keep cans on a shelf, not the floor, so dampness doesn't rust them.
- Near heat: USFA says to keep anything that can burn at least 3 feet from the furnace, oil burner, water heater and wood stove.
- Spray paint: store it upright in a ventilated area out of sun, between about 50 and 80 degrees, per Sherwin-Williams.
Oil-based paint, varnish and thinners are a different case. USFA advises keeping paints and varnishes in a shed away from the house, and storing anything that can catch fire away from your home and out of the sun. Buy only what the job needs and get rid of extra thinner and oil-based leftovers rather than keeping years of it. If you do keep flammable cans in an attached garage, the fire separation between the garage and the house matters, and so does having working smoke alarms.
Oily rags need their own plan
Rags soaked with oil-based stain, linseed oil or similar finishes can heat up and catch fire by themselves as they dry, with no spark. The National Park Service says to spread rags in a single layer on concrete, out of direct sun, with the corners weighed down, until they're hard and brittle. USFA's other option is an airtight container kept away from heat. Never leave them in a pile, a bucket or a trash bag. This comes up most after staining or resealing a deck.
Signs a can should go
Sherwin-Williams says opened latex paint keeps about two years and oil-based paint can last up to 15 if stored well. Paint is done when it smells sour or like rotten eggs, or has jelly-like clumps. A rusted, bulging or leaking can is a different problem: EPA says corroding containers need special handling, so call your fire department or local hazardous materials office for instructions instead of pouring it into another container.
Getting rid of leftovers in Philadelphia, Bucks and Montgomery counties
Latex (water-based) paint isn't hazardous waste in Pennsylvania. Philadelphia, Bucks County and Montgomery County all say to dry it out first, by leaving the lid off or stirring in cat litter or another absorbent, and then put it in the regular trash. Bucks and Montgomery County collection events don't take it. Montgomery County's test for dry: push a screwdriver in, and if it won't go in, it's done. The dried can goes in trash, not recycling.
Oil-based paint, stain, varnish, thinner, mineral spirits and spray paint go to a household hazardous waste collection, never the trash, a drain or a storm inlet. These are one-day events; Bucks County says there's no year-round drop-off site.
- Philadelphia's last 2026 event is Saturday, Nov. 7, 9 a.m. to 3 p.m., at 3901 N. Delaware Ave. in Port Richmond. No registration is needed, and it's open to residents of Bucks, Chester, Delaware, Montgomery and Philadelphia counties.
- Bucks County's 2026 events have ended. They run 8:30 a.m. to 2 p.m., need no registration and accept up to 25 gallons or 220 pounds per vehicle.
- Montgomery County's events run spring through fall and require a free online ticket for each vehicle.
Bring everything in its original, labeled container with the lid tight, and don't combine leftovers. Philadelphia asks residents to bag any container that won't close tightly, wrap glass in newspaper and pack it all in a sturdy box. Business and contractor waste isn't accepted. For oil-based paint with no event nearby, Pennsylvania DEP lists a hazardous waste hotline at 1-800-346-4242.