Step-by-Step Guide to Restoring Old Paint
If you’ve ever painted a room in your house or apartment, you know how painful it is to store leftover paint. You pour the excess paint from the pan into a paint can, hammer the lid on, and stick the old can somewhere off to the side, where you quickly forget about it. Then the day comes when you need to touch up the room or completely repaint it, and you pull the old can out of its hiding place only to discover that time has not been kind to your paint.
If your old paint hasn’t aged well—it’s crusty, chunky, or otherwise questionable—but you really don’t want to spend the money on a new can just for a little touch-up, you can try reviving the paint. This happened to me recently: I had an old five gallon bucket of gray paint with about a gallon of paint left in it, and when I opened it it looked like this:
But I didn’t want to run out and buy a fresh gallon for a small job, so I decided to bring this paint back to life.
First, a few caveats: not all paint can be brought back to life. It should be mostly liquid, even if it’s large and skinned – if it’s completely hardened, just toss it in the trash. A few more things to check:
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Form. If you open a can and see that it smells musty (or worse) or has growth on it, it shouldn’t be used—even if you stir it and shape it into a usable shape, you’ll be leaving mold spores on your walls . Although modern paints typically contain biocides that inhibit mold growth for years to come, different climates or variable storage conditions can affect their effectiveness.
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Thin. If you’ve already thinned the paint with water (for water-based paints) or paint thinner (for oil-based paints), you probably won’t be able to put it back.
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Frozen. If the paint has cured at any point, you’re probably done. Cured paint will have a “cottage cheese” texture.
If you see these signs, throw away the paint and resign yourself to buying a new can. Otherwise, come with me on an adventure of color resurrection.
How to revive old paint
My paint was never thinned and although it was thick, it was still runny. It didn’t smell bad, so I thought I had a good chance of getting it back. Here’s what you’ll need on hand to try it:
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Bucket. Here you will collect animated paint.
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Screen. You can buy disposable paint filters or paint filter bags , but you can also use old aluminum window screen or a piece of fiberglass mesh. I had a bunch of fiberglass screen left over from another project, so I cut a piece of it.
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Drill with blade bit. You can stir the paint by hand, but it is much easier to purchase a drill attachment .
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The paint is thinner. If your paint is water-based, you can thin it with a little warm water. My paint is oil based so I need a thinner – I had mineral spirits on hand so I used that.
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Masking tape. Any tape, really, but masking tape is the easiest to work with here.
Once you have all your materials, the first thing you need to do is thin the paint a little. Add a small amount of water or paint thinner, then stir the paint, starting on low and gradually increasing the heat.
This should eliminate the worst bits. How much to thin your paint is more of an art than a science: you don’t want to thin it too much and make it watery. I didn’t try to remove every bit of hardened paint and was very conservative in my thinner choice. You can always add a little more and mix again, but you won’t be able to remove the excess thinner once you’ve added it.
Next you screen the paint. Attach the screen to the bucket – in my case I simply wrapped the fiberglass screen around the lid and glued it in place:
I then poured the partially thinned paint into the bucket through the filter:
I let the paint flow through the filter for a few minutes. This filtered out the remaining chunks, leaving a supply of usable paint in my bucket:
I didn’t need much; Honestly, if you’re going to repaint an entire room, you probably shouldn’t rely on old paint that you’ve thinned and filtered. But for a little touch up, it saved me from having to run out for a new can of paint. It worked well, the paint adhered without problems and blended quite well with the old paint. I plan to prime and paint the room again next year so it doesn’t last forever. When I was done, I tossed the rest at the city recycling center so it would no longer haunt my closet.