Why Your Oil Painting Brushes Keep Splitting (and How to Fix It)

Close-up of oil painting brushes showing old split brushes.

Few things are more frustrating for an oil painter than watching a once-perfect brush splay into a wild, frizzy mess. Whether you’re using expensive natural hog bristles or budget-friendly synthetics, split brushes can ruin your paint application and make fine detail work nearly impossible.

But don’t toss them out just yet — there’s a good chance you can restore and prevent the problem. Let’s look at why your oil painting brushes split and what you can do to fix them.

Residue Buildup: The Hidden Culprit

Over time, small amounts of paint and medium can dry near the ferrule (that metal band that holds the bristles), forcing the bristles apart. Even if you think your brush is clean, residue might still be hiding deep inside.

How to fix it:

• Soak your brush in odorless mineral spirits or a dedicated brush cleaner for a few hours.

• Gently work out any hardened paint using your fingers or a soft brush comb.

• Wash thoroughly with mild soap (like The Masters Brush Cleaner).

• Rinse, reshape, and let the brush dry flat or bristles-down.

  
  

  💡 Tip: Avoid using hot water during this step — it can loosen the glue inside the ferrule.

Rough Cleaning or Poor Storage Habits

How you clean and store your brushes has a big impact on their lifespan. Scrubbing the bristles against the bottom of a jar or leaving them standing in solvent can permanently bend and split them.

Better habits:

• Wipe off excess paint before rinsing.

• Swirl gently in solvent — don’t jab or press down.

• After cleaning, reshape the bristles into their natural form.

• Let them dry flat or with bristles pointing downward .

  
  

  💡 Tip:  Never leave your brushes sitting in solvent or water — it destroys both the bristles and the handle over time.

Overloading Your Brush with Paint

It’s tempting to scoop up a big, juicy load of paint — especially when you’re working thickly or impasto-style. But packing too much paint into the bristles causes it to creep up toward the ferrule, where it dries, stiffens, and permanently splits the hairs.

How to avoid it:

• Load your brush with just enough paint to cover about half the bristle length.

• If you need more coverage, reload more often instead of overloading once.

• Wipe off excess paint on a rag before switching colours or taking a break.

  
  

  💡 Tip: Overloaded brushes not only split faster but also lose their snap and make colour control harder.

Old or Low-Quality Bristles

Even with perfect care, natural bristles eventually lose their spring and shape. Cheap brushes tend to split faster, especially if the bristles weren’t properly sorted or glued at the factory.

What you can do:

• Condition the bristles with a tiny amount of linseed oil or the masters brush cleaner after each cleaning.

• Use older brushes for texture work, rough blocking, or gesso.

• Invest in a few high-quality brushes for fine details and glazing — they’ll last longer and behave more predictably.

Using Vegetable Oil for Cleaning Oil Painting Brushes

Yes — but with important caveats.

Vegetable oil can help clean or condition oil painting brushes in a pinch, but it’s not ideal for long-term use.

✅ When It Works

For initial paint removal: You can use vegetable oil (like canola, safflower, or olive oil) to loosen and wipe off fresh oil paint before using solvent or soap.

• Pour a small amount onto a rag or paper towel.

• Gently work it into the bristles to soften the paint.

• Then follow up with soap and warm water (or a proper brush cleaner).

• As a temporary conditioner: A drop of oil rubbed through clean bristles can help keep natural hair soft between sessions.

⚠️ When to Avoid It

• Never use vegetable oil as your only cleaner. It doesn’t remove pigment or binding oils completely, leaving a residue that will eventually turn sticky or rancid.

• Avoid olive oil in particular — it goes bad fastest.

• Never mix it with solvents or leave brushes soaking in it; this can damage the bristles and loosen the ferrule glue.

✅ Best Practice

Use vegetable oil only as an emergency cleaner when you’re out of solvents — but always follow up with proper soap and warm water. For long-term care, switch to artist-grade cleaning and conditioning products.

Environmental Factors: Dry Air & Heat

Natural bristles are just like hair — they can dry out, especially in heated or air-conditioned rooms.

To prevent dryness and splitting:

• Occasionally coat clean bristles with a drop of linseed oil to keep them supple.

• Store your brushes in a cool, dry, but not overly dry environment.

The “Hot Soap Wrap” Rescue Trick

If your brushes are already badly split, try this gentle reshaping method:

1. Clean the brush thoroughly.

2. Dip the bristles briefly in very hot (not boiling) water.

3. Reshape immediately using your fingers.

4. Wrap the bristles in toilet paper or plastic wrap to hold their shape while drying.

   
   

This can help natural bristles “remember” their original form.

The Natural Reinvestment Cycle

Even the best brushes won’t last forever — and that’s okay. Every painter goes through a natural reinvestment cycle, where older brushes are retired, and new ones take their place. Building this into your practice helps you maintain consistent results and avoid frustration.

How to approach it:

• Expect to replace heavily used brushes every few months to a year, depending on your painting frequency.

• Keep a small budget for regular brush upgrades, just like you would for canvas or paint.

• Reassign worn brushes to underpainting, scumbling, or experimental work rather than discarding them.

  
  

  💡 Tip: Treating brushes as part of a living toolkit — rather than permanent tools — keeps your workflow fresh and your results consistent.

🖌️ Keep Your Brushes Painting Smoothly

Split brushes are usually a sign of neglect, residue, or harsh treatment — but with a bit of care, most can be saved. Remember: clean gently, reshape after every use, and condition once in a while. Your brushes will thank you with smoother strokes and longer life.

Have your own brush-saving tricks? Share them in the comments — every artist has a favourite restoration hack!