You come back to the hobby desk after a few days away, flip open your wet palette, and… there it is. Fuzzy green or black patches growing across the sponge and paper. It smells faintly like something you’d find behind a college refrigerator.
Wet palette mold is the single most common complaint in miniature painting. It happens to beginners. It happens to painters who have been doing this for years. And once you understand exactly why it happens, it’s completely preventable.
Here’s the full breakdown: what causes it, the free fixes you can try tonight, and the one upgrade that eliminates the problem at the source.
Why Wet Palettes Grow Mold
A wet palette is, by accident, a nearly perfect mold incubator. You’ve got moisture (the whole point), an organic material the mold can eat (the paper), warmth (room temperature is ideal for mold growth), and paint residue providing additional nutrients. Leave that combination sealed and sitting for more than a day or two and you’re basically running a biology experiment.
The sponge is usually the main culprit. Inexpensive palette kits use standard cellulose foam — the same stuff in kitchen sponges — and cellulose is an organic material mold actively colonizes. The longer it stays wet, the faster mold takes hold.
The paper membrane contributes too. As it breaks down over time, it gives mold more material to feed on. Changing the water doesn’t fully solve this because the paper itself is degrading in place.
The Free Fixes (Start Here)
Before spending anything, there are several approaches that can dramatically slow down wet palette mold using things you probably already have.
Add a Few Drops of Mouthwash
This is one of the most widely recommended tips in the r/minipainting community, and it works. Add two or three drops of Listerine — or any alcohol-based mouthwash — to the water in your palette reservoir. The antimicrobial compounds slow mold growth significantly. Use just a few drops; you don’t want it foaming or affecting how your paints behave on the paper.
A drop of dish soap works on similar principles if you don’t have mouthwash handy. Neither option is a permanent fix, but both are worth trying immediately if you’re dealing with recurring mold.
Put Copper in the Water
Copper has natural antimicrobial properties and can slow mold growth when placed in the water reservoir. A pre-1982 US penny (which is 95% copper), a small piece of copper pipe, or any small copper object placed under the sponge or directly in the water will help. It won’t stop mold entirely, but it’s a genuinely useful addition to any of the other methods here.
Stop Leaving Stagnant Water in It
Stagnant water is the core problem. If you’re not painting for more than two or three days, the water stops moving, oxygen depletes, and mold moves in.
A simple rule that makes a real difference: if you’re not going to paint for more than two days, dump the water out, let the sponge dry completely, and re-wet it fresh next session. Mold needs moisture to survive. Take that away during longer breaks and you break the cycle entirely.
Clean and Dry the Sponge Regularly
Rinse your sponge under warm water after sessions, squeeze it out fully, and let it air dry when you’re stepping away from the hobby for a few days. If it’s already showing discoloration or has a smell, it’s compromised — cheap cellulose sponges under regular use typically need replacing every few weeks.
The Actual Fix: Better Foam
The tips above help, but they’re workarounds for the underlying issue: standard palette foam is made of cellulose, which mold colonizes. The permanent solution is foam that mold can’t take hold on in the first place.
This is what separates the Redgrass Everlasting Wet Palette Painter Lite from cheaper alternatives. The foam Redgrass uses is naturally mold-resistant — not treated with chemicals that wear off over time, but made from a material that mold simply doesn’t colonize. No additives, no smell, no special treatment required. You rinse it with fresh water occasionally and it keeps performing.
The Painter Lite comes with 50 hydration paper sheets and two foam pads. You’ll notice the difference in how long you can leave it sealed between sessions — painters regularly report going a week or more without mold issues using the Redgrass foam versus days with a standard sponge.
If you’ve been battling recurring mold with a basic palette and cycling through the workarounds above, this is the upgrade that actually solves the problem rather than delays it.
Should You Step Up to the Everlasting Wet Palette V2?
If you’re buying new, the Redgrass Everlasting Wet Palette Studio V2 is worth a look alongside the Painter Lite. The V2 uses a fully watertight seal — secure enough to put in a bag without leaking — which does more than just prevent spills. A better seal also means less stagnant air inside the palette between sessions, which reduces the conditions mold needs to grow on the paper surface.
From a pure mold prevention standpoint, both palettes use the same naturally mold-resistant foam. The V2’s advantages are the improved seal, a slide-lock system for accessories, and the option to add a glass palette insert for oil work. If you’re buying your first quality wet palette, the Painter Lite is the more accessible starting point. If you already use a Redgrass palette and want to upgrade, the V2 is the step up.
What to Do If Your Palette Is Already Moldy
If you’re dealing with mold right now, here’s the recovery process:
Dump everything out. Scrub the palette body with warm water and a small amount of dish soap, rinse thoroughly, and let it fully air dry before reassembling. The paper is a write-off regardless — throw it out and start fresh. The sponge can sometimes be salvaged by rinsing, scrubbing, and letting it dry completely in direct sunlight, but if it’s deeply discolored or still smells after drying, replace it.
Going forward, pair the clean palette with one or two of the prevention methods above — or make the foam upgrade and skip the mold problem entirely.
Common Questions
Does storing the palette in the fridge help?
Yes, significantly. Cold temperatures slow mold growth dramatically. Refrigerating a sealed wet palette during multi-day breaks is a legitimate and widely used technique — just let it return to room temperature before opening, or you’ll get condensation on the paper. This works best as a supplement to other methods rather than a standalone fix.
Will higher-quality palette paper reduce mold?
It helps at the margins. Thicker, slower-degrading paper like the hydration sheets included with Redgrass palettes gives mold less to feed on than cheap alternatives. But the foam/sponge is the primary mold site — better paper alone won’t solve the problem if the underlying foam is cellulose.
Can I use my wet palette with the mouthwash trick indefinitely?
The mouthwash approach slows mold down considerably and many painters use it successfully for years with otherwise standard palettes. The main limitation is that you have to remember to add it every session and refresh it when changing water. If you’re okay with that routine, it’s a perfectly valid long-term approach. If you want something you don’t have to think about, the foam upgrade is the lower-maintenance solution.
The Short Version
Wet palette mold happens because standard cellulose sponges are organic material that mold colonizes readily. The free fixes — mouthwash drops, copper in the water, drying the sponge between longer breaks — can all slow the problem down significantly. The permanent fix is switching to a palette with naturally mold-resistant foam. The Redgrass Everlasting Wet Palette Painter Lite is the most straightforward way to get there, and it’s the palette that the miniature painting community keeps recommending for good reason.
Start with the free methods tonight. If you’re still fighting mold three weeks from now, you’ll know what to upgrade.
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