Properly stored paint can last many years.
The leftover (latex) paint in your basement will, sooner or later, become a disposal problem. Here's how to make sure your next can of paint remains in usable condition.
As a general rule of thumb, if a can of paint is less than one third full it is not worth storing - leave the lid off and let it dry completely. Then, leave it out with your household trash - dry paint is considered disposable household trash.
Important to note: liquid paint is considered hazardous waste and must be disposed of accordingly - the Jackson County Household Hazardous Waste Disposal facility is a great option.
Paint should always be stored indoors so that it can not freeze. If it has ever frozen, it is now toast. A good test for frozen paint: stir it. Stir-able paint should be OK, if it feels like a brick it's probably been frozen.
Plastic wrap will keep paint out of the "gutter" at the top of the can and will keep paint from drying on the lid. It's best to plan ahead: as soon as you open the can that will likely be leftover, wash the lid and use a pour spout to keep the gutter clean. Plastic wrap will also keep the lid from contacting the can where corrosion can start. See the photo.
Now, before the lid goes on us committed Paint Geeks will exhale long and slow into the can. This will displace oxygen (dries paint) with CO2 (not so much).
Now, the lid - securely. Thumb-pressing is adequate; hammering is excessive and will usually damage the seal.
Finally, upside down storage means the paint in the can seals the lid, making premature drying that much less likely.
Industry experts acknowledge that just about 0% of the paint stored in your basement is likely to ever see the light of day, so the whole storage thing may be a triumph of Hope over Reason. At least now you've got reason to hope that your paint will remain in usable condition.
Still not sure if it's usable? Give us a call - we'd be happy to take a look.