How to Clean oil-based Polyurethane Brush?

Randy Charles
Professional Painter

Randy Charles is the owner of, a website dedicated to providing information, tips, tricks, and news about all things paint. With over 10 years...Read more

Polyurethane is a type of varnish used on wood to protect it and make it shine. When you use the oil-based kind, it creates a tough, protective layer. But once it dries, it’s really hard to get off. This is great for your wood projects because it lasts long and looks good. But when it comes to your brushes, this means you have to clean them well right after using them. If the polyurethane dries on the brush, it can ruin the bristles.

How To Clean Oil-Based Polyurethane Brush?

Short Answer:

To clean an oil-based polyurethane brush, you need to use a solvent like mineral spirits or paint thinner. These liquids break down the polyurethane so you can wash it out of the brush. It’s important to do this in a well-ventilated area because these solvents can be strong and smelly. Also, wear gloves to protect your hands. Even though cleaning oil-based polyurethane brushes takes some extra steps, it’s worth it. This way, your brushes stay in good condition, ready for your next project.

What You Need for Cleaning:

  1. Mineral spirits or paint thinner
  2. Container
  3. Gloves
  4. Old newspapers or drop cloth
  5. Soap
  6. Water
  7. Brush comb or old fork
  8. Paper towels or old rags

Step 1: Pour Solvent into a Container First, you need a container like a jar or a small bucket. Pour mineral spirits or paint thinner into it. Make sure you have enough to cover the bristles of your brush.

Step 2: Dip and Swirl the Brush Put your brush into the solvent. Gently move it around and press it against the container’s side. This helps the solvent get into the bristles and start breaking down the polyurethane.

Step 3: Wipe the Brush Take your brush out of the solvent. Use paper towels or an old rag to wipe off the polyurethane that’s loosened. Be gentle but thorough.

Step 4: Repeat if Needed If your brush still has polyurethane on it, dip it back into the solvent. You might need to do this a few times. Change the solvent if it gets too dirty.

Step 5: Wash with Soap and Water After the majority of the polyurethane is off, wash the brush with soap and water. This helps remove any remaining solvent and polyurethane. Swirl the brush in soapy water and rinse it under running water.

Step 6: Comb the Bristles Use a brush comb or an old fork to gently comb through the bristles. This removes any remaining polyurethane bits and helps keep the bristles straight.

Step 7: Rinse Again Give the brush one more rinse under running water to make sure all the soap and polyurethane are out.

Step 8: Dry the Brush Shake off excess water from the brush. Then, use a clean rag or paper towel to gently press on the bristles to remove as much water as possible.

Step 9: Reshape the Bristles Use your hands to reshape the bristles to their original form. This is important so your brush dries properly and is ready for the next use.

Step 10: Let it Dry Lay the brush flat on a clean surface or hang it up to dry. Make sure it’s completely dry before you use it again.

Cleaning oil-based Polyurethane Brush Without a Mineral

Cleaning an oil-based polyurethane brush without mineral spirits can be a bit challenging, but it’s possible. Here’s how you can do it using items you might already have at home.

Use Vegetable Oil and Dish Soap

  1. Vegetable Oil: First, pour some vegetable oil into a container. Dip your brush in the oil. The oil helps loosen the polyurethane from the bristles.
  2. Work the Oil: Press the brush against the container’s sides. Move it around to work the oil into the bristles. This helps break down the polyurethane.
  3. Wipe the Brush: Take the brush out and wipe it with a rag or paper towel. This removes some of the polyurethane.

Soap and Water Cleaning

  1. Dish Soap: After using oil, put some dish soap in your hand or a container. Dip your brush in and swirl it around.
  2. Scrub Gently: Use an old toothbrush or your fingers to gently scrub the bristles. This helps remove the polyurethane.
  3. Rinse: Rinse the brush under running water. Keep rinsing until the water runs clear.

Final Steps

  1. Comb the Bristles: Use a brush comb or an old fork to straighten the bristles and remove any remaining bits.
  2. Dry the Brush: Shake off the excess water. Then, gently press the bristles with a clean rag or paper towel to dry.
  3. Reshape and Store: Reshape the brush bristles and let the brush dry completely before storing.


I hope this guide makes it clear how important it is to clean your brush after using oil-based polyurethane. You can use mineral spirits or things like vegetable oil and soap. The main thing is to clean your brush well. This helps your brush last longer and be ready for your next painting job. It’s not just about not spending money on new brushes. It’s about taking care of what you have. If you clean your brushes right, they work better and last a long time.

Randy CharlesProfessional Painter

Randy Charles is the owner of, a website dedicated to providing information, tips, tricks, and news about all things paint. With over 10 years of experience in the painting industry, Randy has become an expert in the field and is passionate about helping others learn more about painting. He has written numerous articles on the subject and is committed to providing accurate and up-to-date information to his readers.

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