Leftover paint can, in fact last a very long time, but you must remember that, over time the paint you did use on that house painting project will likely have faded or darkened somewhat, and usually not evenly. For example, if the room you originally painted was used by a smoker over even several months, the paint in the room – assuming they did their smoking in that room – will have darkened to the point you would notice it. If you try to touch up scuff marks, part of a wall you had to repair, or other area, the ‘old’ paint will make the new paint stand out.
Sometimes keeping the old paint is more useful for keeping an exact record of what paint you purchased originally. It is helpful of you are going to, for example, paint the hallway beside a room, and wish to score a very close color match. In this type of scenario, because the rooms are likely divided by a door frame, an archway or such, you have a ‘breaker’ between the old and the new paint. It’s not so important then.
I hate to say it, but the moment you open a can of paint, the paint itself starts to change. It is exposed to the air, and begins the drying process even a little. Paint is meant to begin drying the moment it hits the air, and so it should. It is a quality of good paint! The only problem is, now you have an inch of paint in the bottom of a on-gallon paint can, and it is a little dried out. You put the lid on it, and there it stays for seven years. It won’t be the same when you open it up.
Whatever chemical process has begun inside that mostly empty can, it can be slowed significantly if you store it in a cool place. Not a place that goes well below freezing – because that, too, can damage paint (although paint does have a much lower freezing point than water does) – but rather, a place in the house that is not heated, not exposed to sunlight, and stays above freezing. For a lot of homes, that’s somewhere in the basement. If you have one of those post World War II houses that were built with a basement that could double as a nuclear fallout shelter (yes, imagine they believed such a war was survivable, or that you might want to be around after one), you may already have a great place to store leftover paint. In Seattle, Kirkland or Bellevue, it never gets so hot that paint would be compromised in the basement there, so it’s likely the best place.
Even the slightest gap in the lid seal of your unused paint will allow the paint to dry out completely over time, and the paint will therefore become useless. What I have done in the past is to clean the lid of the paint can at the same time you are cleaning your paintbrushes for storage. That way you have what is effectively a ‘new’ paint can lid. If the original paint can is not usable, consider pouring the remaining paint into a truly sealable metal container or glass container. Metal is better than glass, by the way, particularly if the paint is not going to be stored in a dark place.
This one is a bit more difficult to do because once you’re done with the project, it’s hard to get back in the car, and drive off to buy more of the same paint. Still, a quarter gallon of the same paint can be the perfect solution five years later when you need to touch up after that drywall plumbing repair! It also takes up far less space and is not as unsightly as a big old paint container all splashed up with dried out paint.
Keeping small containers of the paint you used, by the way, makes the house more attractive in the event you are selling it. Imagine a potential buyer seeing you neat, sample collection of all the paint you used in each room. Not a big thing, but it sends a message of careful house maintenance, and leaves a few more avenues of convenience for any future buyer.
Not everyone can guess which paint was used where, especially where accent colors used were only a slight variation. For example, if you painted the walls of your kitchen pearl white, and the kitchen ceiling brilliant pearl white, you need to write with a sharpie on each container which wall, ceiling or other surface each variation was used on.
Throw out what’s nearly empty
The greater the ratio of air there is to paint in the can, the more likely the little bit of paint there is might be unusable as the years pass. If you’re hoping to hold on to an ounce of paint in a two gallon can, might I suggest you simply throw it out.
Rather than keep a small amount of paint, or throw anything out, I have in the past simply used up the extra bit on a wall or trim that I believe might get more wear and tear. It’s a little more coating than you would perhaps deliberately plan and pay for, but it might be better than throwing the two ounces of paint away.
Storing the paint in a cool, dry place that does not freeze is the way to go. Different paints freeze at different temperatures, so ask your paint supplier for the low down on the exact paint you are using.
And remember, even though paint, when it is sitting on the wall for years and my be completely freeze-resistant, wet paint behaves far more differently. It’s the liquid in paint that does the freezing, which is not a problem when the paint is dry and there’s no ‘liquid’ in it anymore. As long as it’s in the paint can, it is subject to damage by freezing. It’s why, by the way, many painting contracting companies refuse to do any outside work, even if it’s not raining, when the temperature might reach freezing point. Wet paint on a wall that’s far below freezing can be severely damaged.
If you have several people doing the actual painting work, you might end up with leftover paint in several cans. It’s probably obvious to say that you should pour all of the leftovers into the same can. That’s assuming, of course, it’s the exact same paint!!!
If you have a painting contractor do the work, you might ask to keep the leftovers. They will probably offer that, but some don’t. It depends on the contract. If you did the paint buying and the contracting company did the painting, then the leftovers clearly belong to you. Some painting contractors might, for example, regularly paint using the same white, house after house, office after office, and they simply use up what they didn’t finish on the last project.
It always helps to ask, and certainly, every painting section of a home stores’ supply center will be able to advise you on how to store leftover paint.
Until next week!