It seems that this topic has popped up quite a bit more in my YouTube comments lately, so I thought I’d address it in detail. I genuinely wonder how many people struggle with this issue? Maybe I should do some kind of public poll.

In This Post

What is mold?

It’s a fungi, but not a fun guy.

I recently heard a Ted Talk about how amazing fungi is. And I also learned it’s literally everywhere. At all times there are fungi spores on almost every surface on earth. Some environments promote faster growth, while others don’t allow it to grow at all.

When you close the palette and it seals tightly, it creates a moist environment for those spores to reproduce. Contrary to what you might believe, fungi is not trying to ruin your life. It’s just doing it’s thing. The only thing it can do, really.

Spores can travel via air, water, and stick to almost any surface, including your paint.

Mold can be fuzzy, slimy, or look like discolored dots on your gouache. Sometimes it’s milky white and other times it’s brown or black.

What to do if you already have mold in your gouache palette?

• Remove and discard the moldy gouache and thoroughly clean the palette out.
• Disinfect your palette, either with distilled white vinegar (straight out of the bottle) or rubbing alcohol. Do this in a sink, and use gloves to avoid getting the solution on your hands.
• If your palette is metal, let it soak in boiling water. (Note: many plastics will melt in boiling water, try that at your own risk)
• Disinfect your brushes by scrubbing with dish soap and warm water (not boiling! that could melt synthetic hairs).
• I regularly use Master’s Brush Cleaner & Conditioner to clean my brushes

3 Ways to Avoid a Moldy Gouache Palette

Now let’s talk about how to avoid mold in the first place.

How to use Clove Bud Oil to prevent mold in your gouache palette

The rule of thumb is to use as little as you need to get the job done.

• First mix a diluted solution – fill a 50ml plastic spray bottle with water, add 10 drops of clove but oil. Shake vigorously.
• Spritz gently into your clean palette.
• Add your gouache to your palette.
• Give a quick spritz of the solution to the top of your gouache.
• Stir each color individually with a toothpick (clean toothpick after each color so your don’t mix your colors)
• Don’t go overboard and spray too much, as too much oil can change how the paint behaves.

If you have FREQUENT problems with mold, especially in specific colors, try this:

• Add one whole drop of clove bud oil to each color that has issues.
• I know I said don’t use too much oil, but I found that one or two drops doesn’t really change the consistency too much, plus I dilute my gouache with water when I use it.

2. Open and Use the Gouache Palette Frequently (at least once a week, if not every few days)

This is my preferred method. By opening the palette and using the gouache, not only does this help prevent mold but it also means you are USING it and hopefully IMPROVING your skills!

So how does this help prevent mold growth? It’s some crazy science thing that says disturbed paint doesn’t give spores enough time to reproduce.

If you don’t have time to paint every few days, put a note on your calendar to stir the gouache. Simply open, stir each color individually with a toothpick, and close. I’ve kept my palette mold-free for years by doing this.

3. Use Distilled Water when Painting

I personally have not needed to try this, but I’ve had many comments on my videos saying this helps. It certainly can’t hurt!

Bonus Tip

Mold likes warm, moist environments. So remove any extra water in your palette before you close it. Try soaking up excess water gently from on top of each color with a paper towel before closing. You can also let it sit opened for 5-10 minutes before closing. And if you still have problems, keep your palette in the refrigerator between uses. I don’t recommend freezing it, because it might cause the palette to crack.

Do Some Brands of Gouache get More Moldy Than Others?

I’m in the process of finding out! I am doing a ‘mold test’ on all of the gouache brands in my gouache database.

It’s on the shelf growing as we speak. I’ll be updating the gouache database page regularly in the coming months.

The Takeaway

Mold likes moist, dark and warm environments. Deny it of these conditions and you’re on the right track to avoiding mold growth in your gouache palette.

Some cleaning or additives can be useful, but most importantly, USE THE GOUACHE frequently!

Watch my video about this topic: