How to Use Walnut Oil to Clean Your Brushes

Jan 24, 2024

One of the most common concerns our Mastery Program students have when they first begin the oil & drawing section is in regards to the potential toxicity of oil paint. There is a huge misconception that oil paints are toxic, and with the rise in chronic health issues, many artists avoid oil painting altogether.

While we've busted that myth here, let's talk about walnut oil.

During a recent bout of artist's block and resistance, I resolved myself to beat it by touching paint everyday. Even if I couldn't bring myself to put paint to canvas, I would still be connected to the paint itself. This led me to discover natural pigments and start making my own oil paints.

In discovering the process of creating paint, I stumbled upon some seemingly little-known information on walnut oil. In addition to it yellowing less than linseed oil (making it a preferable binder for oil paint), it also holds some incredible natural properties that make it great for a non-toxic way to clean paintbrushes!

Hold up. Before you go throwing out your solvent, there's some things you need to know…

There is a slightly different process for using walnut oil that you'll need to be aware of before swapping out your solvent or turpentine. So let's walk through the steps together.

Step 1: You'll need TWO jars

While artists typically use one jar of solvent to clean their brushes as they paint, you'll want to use two jars for walnut oil.

When I first started using walnut oil, I thought I'd be clever and efficient by only using one jar. I mean, how much difference could it possibly make? I'm not too proud to admit: I was wrong. That second jar is incredibly helpful and an absolute must for clean, non-muddy colors.

You'll want one jar or container to be your “dirty” walnut oil. This is, in essence, what your solvent jar used to be. You can even get a nifty brush cleaning container like this one. Whatever you use is fine, so long as you can get all the bristles of the brush into the oil.

The second jar is much more straightforward. This will be your “clean” walnut oil. It doesn't have to be big or even have that much oil in it. As long as there's just enough walnut oil to swish the bristles of your brush in, that's enough.

Step 2: Get the paint out

So you've planted that perfect brushstroke and now you're ready to switch colors. You'll want to keep a spot to rub out excess paint before sticking it into the walnut oil. Whether that be the lean-to easel you've built and paint on, a spare canvas board you keep near you while you paint, or cotton rag — you'll want something you can use to get as much paint out of your paintbrush as possible.

Once you've used up the paint in the brush, now it's time to dip it into the walnut oil. However, this is important: While walnut oil is effective as cleaning paintbrushes, it also works a bit slower than solvent or other toxic thinners. With this in mind, I highly recommend letting the brush sit in the oil for about a minute before beginning the dabbing-and-tapping process of getting paint out of the brush. I know that probably sounds awful — waiting a whole minute — but I'm telling you… that brief minute of patience will save you a lot of frustration and “re-dips.” It will allow you to clean the brush well the first round of dabbing-and-tapping, rather than feeling like you have to repeat the dabbing process repeatedly to get the brush clean.

Simply dab and tap the bristles against the bottom of the jar, run the brush against the side of the jar to get the excess oil out, and then wipe well with a clean cotton rag (just as you would with solvent).

Step 3: Give it a rinse

Now that the paint is out of the brush, you'll want to give it a quick dab-and-swish rinse in the clean walnut oil.

This will verify to you that there isn't any paint left in the brush, while also ensuring that the oil in the damp brush is clean and won't muddy your colors. DO NOT SKIP THIS STEP. As I said above, when I arrogantly discarded this step out of impatience and lack of understanding, my paint colors suffered.

Learn from my mistakes. Do not be lazy. Just use the second jar. Your paintings will thank you for it.

Step 4: Know these last tips

If you've followed the steps above, you're pretty much set to go. But there are a couple things to keep in mind as you venture forth into the world of walnut oil. Again… learn from my mistakes.

First, walnut oil can be drying if you leave your brushes in it too long. By too long, I mean longer than a week. Many walnut-oil-using artists will keep the tips of their brushes in walnut oil in between painting sessions. I haven't found this to be a necessary step, but there are some benefits to it. Just know that if you choose to utilize this technique, that you don't want to leave your brushes in walnut oil for longer than a week or it can be drying to the bristles.

Second, there is a difference between walnut oil and walnut alkyd. Walnut oil is just that — walnut oil. It is used a binder for oil paints and can be used for cleaning brushes. So think about that… if it's what oil paint is made with, and oil paint can take weeks to dry, that means walnut oil will drastically slow down the drying time of your paint. DO NOT USE WALNUT OIL AS A MEDIUM when painting, unless you intend for the drying time to be much, much longer. (We won't talk about how I learned this lesson.)

Walnut alkyd, on the other hand, is a walnut oil based medium that is used the way most mediums are used — to hasten the dry time. If you'd like to get the benefits of walnut oil but also have your oil paints dry quicker, then walnut alkyd is a great medium to try.

Now you try!

Whether you decide to try it out because health issues have held you back from oil painting or purely out of sheer curiosity and wanting to try something new, we can't wait to see what beautiful art you create with walnut oil as your non-toxic “solvent.”

Have you tried walnut oil or walnut alkyd before? If so, share your art with our encouraging and supportive community of artists and art lovers in the Milan Art Community.

Written by Julie Briggs

Your destiny starts now

No need to wait — get incredible free content to prepare you for The Mastery Program. Join the Mastery Program Waitlist today!

More articles