Many, if not all homeowners know it well: the half-used paint shelf. Somewhere deep in a basement, high in an attic, or out in the garage, there lies a treasure trove of half-used paint cans leftover from projects past. They sit there, waiting. The question is, do they also sit there going bad? Can paint go bad?
Does Paint Go Bad?
To give a quick answer: yes, it does. Like almost anything, paint can go bad eventually. This isn’t the be-all-end-all of paint analysis, though, and there are a lot of nuances in understanding if and when your paint has gone bad.
Understanding Different Types of Paint
The oil vs. acrylic debate isn’t just a struggle for 18th-century portraitists. Modern paints, just like the ones used by Van Gogh, can come with a variety of different bases. Primarily, there’s oil-based paints and acrylic paints, acrylic paints either being latex or water-based.
If you’re looking for a paint that will last a long time on the shelf, oil is the way to go. Unopened cans of oil paint can last up to 15 years without going bad. If it’s been opened, the shelf-life has probably decreased, but not necessarily by much.
An unopened can of acrylic paint will last the oh-so-short period of 10 years before going bad. Like oil paints, if it’s been opened, it will probably sour a little sooner, but that’s just the nature of paint.
How to Tell if Paint Has Gone Bad?
You’re out by the half-used paint shelf in search of a light blue or deep brown to cover up a patch on your wall from an incident you’d rather not talk about. You crack open a can you haven’t used since you painted the house eight years ago, and you suddenly realize you have no idea how to tell if it’s still usable. That where I’m here to help!
1. Smell It
You heard that right. Spoiled paint will have quite the odor to it. This can come from bacteria or mold growing in the paint. You’ve just been lucky enough to catch a whiff of the gases they put off.
2. Is There a Skin?
Much like yogurt or other refrigerated goods, an old can of paint can get a dried layer across the top if it hasn’t been used in a while. Don’t lose hope though, as this dry layer can be removed simply by pulling it off with a paint stirrer or similar implement. If you stir the remaining paint and it all mixes back together, you’re in the clear.
3. Stir It
Paint can often look like it’s gone bad simply because it’s separated. Stir it up, and be patient about it. This can take up to five minutes. If it all comes back together, it’s probably good.
4. Is It Lumpy?
Lumps are not a death sentence for paint. You don’t want your paint to be lumpy, but lumps don’t mean it’s unusable. You can strain the lumps out using a simple paint strainer and be good to go in no time.
If it’s still too thick after straining try adding some water to latex paints and minerals spirits to oil paints to thin back out.
How to Store Paint
The easiest way to keep paint from going bad between uses is to store it properly. Unfortunately, this probably means the infamous paint shelf isn’t the best way to go.
Paint shouldn’t be exposed to sunlight or vast changes in temperature. Though this means your uninsulated garage or attic are out of the question due to temperature changes, a basement is still a viable option.
On the other hand, paint should definitely be completely sealed. An easy way to do this is to put a piece of plastic wrap over the top before tapping on the lid. That way, when you reattach the lid with a few light taps of the hammer, the plastic wrap helps make the seal more moisture-tight. Oh, and mark the date on it. You’ll thank yourself later.
How to Dispose of Paint
Despite your best efforts, paint can and sometimes does go bad. When it does, there are a few options.
First, you can let it dry up and put it out to be picked up with your garbage. You have to dry it up first, though, because it can be toxic. Setting it in the sun for a few days should do the trick.
Second, you can take it to a hazardous waste facility near you. We know what you’re thinking – I painted my whole house in hazardous waste? No. As long as you aren’t eating it, you’re probably going to be fine. It just isn’t good for the environment to pour paint out into the water system.
Congratulations, you are now fully equipped to tell if those twenty-odd cans of paint in your basement are still usable. The biggest thing to remember is that paint can often look spoiled when it isn’t, so try stirring and straining before getting rid of it.
That being said, buying new paint is a lot less hassle than painting your whole house with lumpy, spoiled paint, so make sure to follow your instincts. Worst case scenario, you end up with another half-empty can upon the shelf.
Founder & Senior Editor
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.