The Best Way to Clean Oil-Based Paint off Paintbrushes

Thanks to my miniature misadventures (I’d trademark that if I could), I’ve learned that I should always prime wood before I paint it. And, I’ve learned that I should avoid oil-based paints when I can. That’s mostly because they smell and they’re a pain to clean up.

Unfortunately, the primer I’m currently working through (because I was not paying attention when I bought it (yes, file this under newbie mistakes!) is oil-based. And, given how little of it I use when I do prime, it’s going to take me a loooong time to use it all up. The easy money is on the paint going bad or drying up before I ever finish it off.

That means I’m going to have to get used to working with oil-based paint. Well, really just oil-based primer. And, that means I’ve got to find the best way to clean oil-based paint off my paintbrushes so I don’t destroy them.

Oil and Water Don’t Mix

You can’t use plain old soap — even dish soap — and water to wash a paintbrush covered in oil-based paint. You probably knew that either from experience or reading the label on the paint can. But did you ever think about why?

If you’re like me, you like to cook. And, if you don’t like to cook, you’re still like me in that you probably like to eat (or, at least, know you have to eat). And, of course, you also know you should eat your vegetables.

Pro tip: to make veggies a little more tolerable, chop them up and sprinkle them with some olive oil and salt, toss them in the oven until they are tender. This makes them edible even to those who hate vegetables.

And, if you’re like me, you hate to clean up. In fact, you might suck at it (like me!). But, again, it’s got to happen.

So, you’re cleaning up the pan you used to roast the veggies, and there’s olive oil still on it. Even if you use parchment paper to line your pan (which I highly recommend), the olive oil is going to end up on the pan. No big deal. Oil is slippery and should clean right up.

Except it doesn’t. When you rinse the pan in the water, it beads up and kind of rolls off the oil. You might think that’s because oil is, well, oily, and that’s what oil does, helps things like roll off of it.

But, there’s a far more scientific explanation for this. The short answer is water molecules have polar molecules, and oil molecules have nonpolar molecules. Polar molecules play nice with other polar molecules but don’t play well with nonpolar molecules and vice versa. That’s why it’s easy to dissolve sugar in water — they’re both made of polar molecules. And it’s also why oil and water don’t mix! They are made of opposite molecules.

If you’ve ever poured oil into water (or vice versa), you know what I’m talking about. If you haven’t done it before, you can do that right now. Or check out the pictures. TLDR: the oil floats on the water! From the top down view you can see the large bubbles.

• 

• 

So, to get the pan clean, you add some soap to the water, and that gets your pan clean. Again, the scientific answer is the soap breaks up the big oil beads into smaller beads, which can then mix with the water. How? Soap molecules have two different ends, One loves water, the other hates it. The hate it ends sticks to the oil, the loves it end sticks to the water and surrounds the oil creating a bubble that gets washed off.

For fun, here’s what happened when I added soap to the oil and water. As you can see, the soap kind of obliterated the oil. Also, it’s kind of hard to see the small bubbles the soap turned the oil into, but they are there.

• 

• 

Great, But Why Does This matter?

OK. Cool. So, why can’t you use soap and water to clean the oil-based paint off your brush?

Well, you can, it’s just not great for the bristles. Think about it. When you wash, say your hands or the dirty pan, all the surface area is exposed, so it’s easy to create the “washing off” action. There’s no place for the oil to hide. In a bristle brush, that’s not the case. 

Here’s a picture of my hand and a bristle brush.

• 

• 

• 

As you can see, all of my hand is exposed. But those inside bristles are harder to clean thoroughly because of how they’re arranged in the brush.

There are so many places for the paint to hide!

While it is possible to use just soap and water (and a brush cleaner), honestly, that’s not the best way to clean oil-based paint off anything. You’re going to spend a lot more time cleaning than had you started with something designed to clean oil-based paints.

What You Can Use (And Why They Work)

Science lesson over! Let’s talk about what to use and the best way to clean oil-based paint off your brushes. And, by that I mean, technique. Because when it comes to painting, technique is everything (maybe. I’m not a painter, so I don’t know).

Solvents

Probably the most effective product to clean oil based paint off brushes (and other things, I suppose), is solvents. Specifically, paint thinner or mineral spirits. You can also use turpentine. However, if you’re using shellac, you’ll need denatured alcohol or ammonia.

The good part about these solvents is that they work. They will get the oil-based paint out of your brush every single time. The bad part about these solvents is that they smell, can be kind of dangerous (flame on, anyone?) and they aren’t so fantastic for the environment (as in, you can’t rinse this stuff down the drain or toss it in the trash).

Oil

The definition of a paint thinner is that it’s a solvent. The technical definition of a solvent is “able to dissolve other substances.” OK, then.

But, if you’ve ever checked out the ingredient label on paint thinner or mineral spirits, you might find some interesting information. Here’s a picture of the bottle of mineral spirits I’ve got:

On the ingredients list (and I use that term loosely), you’ll see “Contains Petroleum Distillates.”

Petroleum Distillates. Hmmm. What are those?

Get this. They’re solvents made from crude oil.

While I don’t recommend going out and buying a barrel of crude oil for your oil-based painting needs, it does tell me that oil can act as a solvent for oil-based paint. 

For the record, I scoured the internet to try to find out why this is the case, but couldn’t find an answer. If you know why oil will break down oil, please chime in in the comments. But, because I’m going to have to draw my own conclusions, I’m going to go with “magic” and move on.

So, if that’s the case, can you use plain old oil (like vegetable oil) to clean up oil-based paint on paintbrushes, and everywhere else?

Yup. 

I know because I’ve done it. And, you can use it to get the paint off your hands, too. I do not know if it will get paint out of your clothing. But, really, you shouldn’t be painting in your Sunday best, anyway. I mean, if you want to, OK. I won’t judge you, but wear a smock!

Actually, you can use any kind of oil. Baby oil, cottonseed oil, sesame seed oil. Whatever you’ve got, it will work. Because oil is a solvent, and magic makes it work!

OK. Not magic. But science that I can’t explain.

I will say from experience, though, that it is slower than using mineral spirits or paint thinner. So, using oil will require patience and, perhaps, some extra scrubbing on your part. And, remember, the paint is still oil-based paint, so that probably shouldn’t go down your drain. But, if you want a safer, less-hazardous way to clean up your brushes, I say oil is the way to go.

That said, when I’m finished rinsing the brushes in vegetable oil, I follow with soap and water.  They seem OK, but don’t look fantastic when I’m done. That’s what led me to research the best way to clean oil-based paint out of paintbrushes. It turns out that while vegetable oil is fine for cleaning, my technique needs a bit of work.

The Best Way to Clean Oil-Based Paint off Paintbrushes

The best way to clean oil-based paint of your brushes is the one that works best for you. Hokey, I know, but true. If solvents are your thing, great, just be careful. If oil is what you want, fine. Go for it.

Just know that no matter how you decide to clean your brushes, it’s going to take more than a quick rinse in whatever you use. Cleaning up your brushes takes a fair amount of patience, time, and elbow grease.

With a solvent 

Going the solvent route? Cool. Follow these steps to get your brushes back in shape.

1. Pick the right place

Always, always, always (I can’t stress this enough), if you use a solvent to clean your brushes, do so in a well-ventilated space. Outdoors is best, but if that’s not possible, make sure there’s plenty of air-flow wherever you work.

2. Gather your supplies

Get everything you need before you start cleaning. Trust me. There’s nothing worse than having an open bottle of mineral spirits or paint thinner and realizing you need a container or paper towels or something. 

You’ll need a non-plastic container and your solvent of choice. Have paper towels nearby and wear chemical resistant gloves. The solvent will eat through the wrong kind (which is also why you want a non-plastic container).

Pour just enough solvent into the container to cover the brush bristles. Something tall and narrow is better than wide and flat in this case (like a jar and not a bowl). You’ll use less and cover more.

3. Dip and swirl

Take your paintbrush and dip it in the jar. Feel free to let it sit in the solvent for a few seconds. Then, spin the brush inside the container for about 10 seconds using your hand (or roll it between both your hands). After the 10 seconds is up, take the brush out of the jar and work the solvent into the bristles, trying to get out as much paint as possible. 

4. Rinse and repeat

Rinse the brush in some clean water and test and see if all the paint is out. If you blot a paper towel to the brush, and it comes clean, you can move on to the next step. If there’s still paint in the brush, repeat the process with clean solvent until it’s clean.

5. Flick, clean, and rinse

When all the paint is out of the bristles, flick the paintbrush onto newspaper to get the remaining solvent out of the brush. Clean the brush in warm, soapy water, but only for about a minute to get everything nice and clean without messing up your brushes. Then allow them to air dry.

If you want to take the extra step of combing your paintbrush, you can. This can help get any dried paint you might have missed out of the brush and help you reshape the bristles. You can find a paintbrush combing tool at the hardware store, or use a cat brush (since it’s doubtful you’re using it on the cat!).

6. Use caution

So, it’s easy to think you can do this over the sink. After all, you’re just rinsing the stuff down the drain, and that’s fine, right?

Well, it’s not. For starters, solvents are a fire hazard because they only need to heat to 104 degrees Fahrenheit to ignite. That alone should be reason enough for you to say “no way” to the drain. 

It’s also why you can’t toss it in your garbage can and send it to the landfill. I’m not going to give you another science lesson, but let’s just say that not properly disposing of this stuff can result in spontaneous combustion. For real.

Whether you used old rags or paper towels, make sure you lay them out flat to dry before you toss them in the trash. Ideally, you can lay them outside for a few days. When those are dry, take the rags, the used solvent, and anything covered in it to a local hazardous waste facility. Not sure where your closest one is? The EPA has a list of all the state agencies that handle this stuff.

With oil

If solvents aren’t your thing, use regular old oil instead. Baby oil, vegetable oil, massage oil (I’m guessing) will all work. Just follow the same steps above to get the brushes clean.

However, just because you’re using plain old oil doesn’t mean you can rinse it down the drain!

Remember, you’re using oil to clean up the oil-based paints. And, what does oil not mix well with? Water. That means that the regular oil you’re washing down the drain could sit in your pipes and cause problems.

Depending on the oil you use, it might be OK to put everything into the trash. But, it might not. For example, baby oil is not a hazardous waste. And, if you use it to clean your paintbrushes, you can put it in the regular trash. But if you use something like linseed oil, you need to take everything to a hazardous waste dump because of how flammable linseed oil is.

Next Time, I’ll Pay Attention

Next time I buy paint or primer, I’ll make sure I check the label. These oil-based paints are a pain, and they stink, too. Plus, given that this is just a miniature dollhouse, I don’t know if oil-based paints are necessary. OK. Not “just.” I get it. But it’s not like anyone is going to play with this (I think).

This dollhouse has, however, rolled around in the trunk of my car, which is a whole other story that I may never tell!

What about you? Any advice or misadventures to share around cleaning up oil-based paints? Let me know in the comments!