Brush Flush: A Brush Cleaner for Oil and Acrylic

Brush Flush is a biodegradable and watersoluble brush cleaner that removes a variety of paints from natural and synthetic brushes. This article tests the effectiveness of the brush cleaner, including whether it can remove dry, hardened paint from brush fibres.

Brush Flush: A Brush Cleaner for Oil and Acrylic

In the Jackson’s studio, our brushes are in constant use. While cleaning them isn’t the most exciting part of studio life, it is a crucial part of maintaining the space. Many of our brushes, especially hog hair brushes, are used for both oil and acrylic, so any oil residue needs to be completely cleaned to avoid contamination. In a brush cleaner, we look for something that cleans quickly and effectively – there is nothing worse than finding a strong colour, like Phthalo Blue, lingering in a brush when you go to use it! We also need a brush cleaner that doesn’t strip the oils from natural brush hairs, which mineral spirits tend to do. I tried Brush Flush in the studio to see if it meets these criteria.

What is Brush Flush?

Brush Flush is a biodegradable, watersoluble, non-flammable brush cleaning product. It is multi-purpose, with applications that go beyond the artist studio. As well as oil and acrylic, Brush Flush is suitable for latex-based paints, varnishes, shellac, and urethane-based paints (such as those used in car paints).
Missing from the list is watercolour. Typically you don’t need to use a brush cleaner for watercolour or traditional gouache because they are resoluble in water. In fact, the surfactants in brush cleaners can destroy watercolour paper sizing if they are not washed out thoroughly.

There are lots of different brush cleaners on the market, and Brush Flush is the most economical of them all – it is considerably cheaper per millilitre than other oil and acrylic brush cleaners.

Using Brush Flush

Brush Flush is a clear, pale yellow and has a slimy, viscous consistency. The bottle states that it is odour-free, but it actually has a pleasant citrus smell which reminds me of some household cleaning products.

Brush Flush can be used at the end of a painting session. I worked a Willow Wolfe Seneca synthetic brush, full of Phthalo Blue oil paint, into the Brush Flush. I agitated the bristles gently against the side of the jar.

Following the instructions on the bottle, I rinsed the brush in warm water and worked it to a lather with the help of a brush egg. It’s amazing how much paint is trapped in the bristles even when it looks clean!

I worked the brush until the water ran clear. Because Brush Flush is watersoluble, it rinses out very easily, which is not something I’ve found with vegetable oil-containing brush cleaners. The brush was completely clean, and not stained by the Phthalo Blue pigment.

Does Brush Flush Remove Dried Oil and Acrylic Paint?

It’s a scenario that I’m sure most painters are familiar with – you leave the studio and forget to wash a brush. When you return the paint has dried, leaving it hard and unusable. It has happened a fair few times in the Jackson’s studio!

Brush Flush claims to remove dry paint from brushes. It recommends leaving them to soak for anywhere between several days and several weeks, agitating them periodically. I gathered some oil, acrylic, and enamel paint-encrusted brushes to see whether Brush Flush could restore them. I also tried soaking a palette knife which had some old dry paint on it (most likely a mixture of oil and acrylic). Having dry paint residue on a palette knife isn’t a problem, but I wanted to see how it would perform. Lastly, I added a white synthetic hog brush that was clean, but stained, to test if Brush Flush has any effect.

After just 30 minutes in the Brush Flush, yellow oil paint began to leach from one of the hog hair brushes. The paint in the brush was completely dry, but it had been thinned with a solvent so it is unsurprising that it broke down first. I also noticed that paint began to peel from the palette knife and the metal brush ferrules.

After 18 hours, more paint had come out of the oil brushes, and the acrylic paint had begun to soften, wrinkle, and peel away from the brush fibres. It’s a very satisfying process to watch, and I recommend using a clear jar so you can see the progress!

After 24 hours, I took all of the brushes and palette knife out of the brush flush and rinsed them. Most of the brushes were completely restored, and the stained brush came out largely stain-free. The enamel and acrylic brush were soft enough to be used, but still had some paint residue in them, so I put them back in the Brush Flush overnight. After this, they were completely free of paint.

Within two days all of the brushes were clean and supple, although most of them needed only 24 hours in the Brush Flush. One of the most satisfying results was how clean and shiny the ferrules were. They looked like completely new brushes. I noticed that some of the older hog hair brushes had become a slightly brassy colour (the third and fifth brushes from the left in the above image) and were left feeling a little dry. This suggests that the surfactants in Brush Flush have broken down some of the proteins and stripped the natural oils from the hair. If soaking natural hair brushes to remove dried paint, I would recommend keeping them in the Brush Flush for the minimum amount of time needed to clean them, and using a conditioning treatment afterwards.

Can Brush Flush be Reused?

Brush Flush is completely watersoluble and biodegradable and can be disposed of down the sink, but it is more economical to reuse it where possible. With some brush cleaners, as well as with solvents like white spirit or turpentine, pigment settles to the bottom of the jar and the clean liquid can be poured off and reused. This isn’t the case with Brush Flush, as the liquid is so viscous that the pigment remains suspended. However, Brush Flush can still be used again and again, either to clean brushes after a painting session or to soak hardened brushes.

How Safe is Brush Flush?

Brush Flush is labelled as non-toxic, but while it is a safer choice than turpentine or mineral spirits it should still be used with care. The SDS (safety data sheet) states that it may mildly irritate the skin after prolonged exposure. As someone with sensitive skin, the small amount that I got on my hands when I was rinsing the brushes didn’t irritate or make them feel dry. It’s definitely preferable to using solvents! However, it is still recommended to wash your hands after any contact with the skin.

Brush Flush bottles have a simple screw top cap, not a child-safe mechanism like some brush cleaners. This is something to be aware of if you work in a space where children might have access to your materials.

Brush Flush is a powerful, no-nonsense brush cleaner. It quickly removes hardened oil and acrylic paint from brushes, however my tests suggest that it can strip the oils from natural hair brushes when they are left to soak for a long period of time. However, when used as an end-of-session brush cleaner, Brush Flush is extremely effective, economical, and easy to use– invaluable for artists who want to keep their brushes looking their best.