How To Remove Polyurethane From Brush

Polyurethane is a very durable and long-lasting type of paint that is often used on furniture, cabinets, or trim. When applied to a surface, it provides a hard finish that is resistant to staining and fading. However, polyurethane can be difficult to remove from paint brushes especially when it comes to re-panting or refinishing something that’s been coated with it. This is because it dries in two hours or less, leaving behind a sticky residue.

Whether you’re a professional or not, taking care of your instruments or tools is a must and your brushes are no exception. Brushes are quite expensive, so conserving them, even if they are old but of good quality, is worthwhile. You can only accept defeat when the bristles are beyond repair. However, in this article, we’ll go over how to remove polyurethane from brush and also provide some pointers on how to avoid this issue in the future.


Types of Polyurethane

There are two types of polyurethane, each with its own unique properties. Depending on the type of polyurethane you’re using, you can clean your paintbrushes after each use and keep them for years if you follow the right process. They include:

  1. Water-based polyurethane: This is a type of polyurethane that can be used to create a variety of finishes, from glossy to matte, and it dries quickly to a hard, durable finish. This water-based type is designed to be safer and easier to use, as well as safer for the environment, and brush cleaning may be accomplished with just plain water.
  2. Oil –based polyurethane: This is an acrylic paint with a polyurethane binder. It is popular mainly because it is water resistant, and produces a hard, durable finish. But depending on the room conditions, it usually dries to touch in about two hours.


How to remove water-based polyurethane from brush

Water-based polyurethane is easier to remove from brush than oil-based, because it does not contain same solvents. Rather than using mineral spirits, it cleans with soap and water.

Things you’ll need:

  • Warm water
  • Container
  • Dish soap
  • Paintbrush comb
  • Paper towels


  1. Soak the brush in warm water

Before soaking, be sure you’re using a water-based product by reading the package. Fill an old jar or container halfway with warm water and a couple drops of dish soap. To release the polyurethane, dunk the brush in water and swirl it around. You’ll observe a change in the color of the water.

  1. Repeat the procedure

When the container becomes too full of polyurethane, empty it and replenish it with clean water. Continue dipping until the water is completely immersed up to the metal cap, as here is where the majority of the paint concentrates.

  1. Go to the sink

Take the brush to the sink and soak it in warm water. Then release the polyurethane and add a few extra drops of dish soap to the bristles. Continue to work on the bristles until the water is clear,

  1. Shake out the brush

To get rid of the surplus water, swish the brush around a few times. Don’t stop until there is no more water coming out. To dry the brush, dab the bristles over an old rag or paper towels. Then use a brush comb to shape the bristles.

  1. Allow the brush to air dry

Hang the brush to dry out by inserting a rod into the handle. Gravity will help the bristles maintain their shapes by straightening them.


How to remove oil-based polyurethane from brush

Removing oil-based polyurethane from your brush is a little more difficult than the latter. It’s not possible to do it without paint thinner or mineral spirits. But keep in mind, mineral spirits can irritate the skin, so you’ll need to wear a face mask, goggles, and protective gloves. They also emit strong scents as well as irritation of the throat and eyes.

Things you’ll need:

  • Warm water
  • Container
  • Dish soap
  • Paintbrush comb
  • Paper towels
  • Paint thinner


  1. Pour paint thinner into a container

Fill a plastic bottle halfway with paint thinner. Enough to cover the bristles up to the ferrule is required (the metal bit that holds the bristles in place). Mineral spirits can be used instead of thinner if you don’t have any.

  1. Dip the brush into the water

Allow the paintbrush to soak in the thinner for about 20 minutes. Then move the brushes from side to side once the time has passed to loosen the polyurethane. As the polyurethane is removed, the thinner will turn a different color.

  1. Repeat the process

Fill a sealed bottle halfway with contaminated thinner, then top it off with fresh thinner and repeat the process. Work the brush back and forth until all of the paint has been removed. When this happens, you’ll see that the thinner remains clear. The thinner cannot be thrown away or washed down the drain. It must be disposed of at designated areas.

  1. Wash away the thinner

Hold the paintbrush under the faucet with dish soap on the bristles. To protect your hands from the thinner, ensure you are putting on some rubber gloves. Work the dish soap into the bristles until a thick lather is formed. After rinsing it under the tap, rub the bristles once more. Each time you complete this process, you’re searching for less suds. The thinner and surplus dish soap will eventually be rinsed from the brush.

  1. Drying time

Using a paper towel or a dry cloth, wipe away the excess moisture from the bristles. The brush can then be hung to dry, and gravity will restore the bristles’ shape. But do not ever leave a brush standing on its bristles, as this will cause the brush to become misshapen.


Other methods of removal include:

Using mineral spirits

  • Mineral spirits have a strong smell, so use a face mask and goggles to avoid breathing potentially harmful vapors. You should also use rubber gloves to protect your skin.
  • Fill the container halfway with mineral spirits, making sure the brush ferrule is completely submerged. Drop the brush in the container once you’ve cleaned off the extra paint. Swish the brush around the container, pressing the bristles against the container’s side. It’s time to clean the brush when no more paint comes off.
  • Dish soap should be applied on the bristles and massaged in. Then, to remove any residual paint, run the brush under the tap. When you’re sure the paint is gone, pat it dry with a paper towel and hang it.


Using fabric softener

  • Add a gallon of warm water to a cup of fabric softener in a bucket. Combine the two items in a mixing bowl.
  • Place your paintbrush in the liquid and rapidly agitate until the paint begins to pull away from the bristles. The color should drop to the bottom of the bucket. Lift the brush out and pat it dry with a paper towel when there is no more paint visible on it.


Using turpentine

  • Before attempting to clean your bristles, wipe off any excess paint. Wrap the bristles in a paper towel and squeeze them out of the ferrule to remove any remaining color.
  • Fill the bottle halfway with turpentine and dip the brush into it. To loosen any leftover paint, swish it around and press the bristles against the sidewalls. Continue doing so until all of the paint has been removed.
  • Hold the brush over the sink and wash it under the faucet with dish soap. Massage the soap into the bristles with your fingertips, making sure it touches every portion, including the ferrule. If there is no more paint on the brush, rinse it under the tap and dry it with a paper towel. Wrap the bristles around the handle.


Is it possible to revive a dried brush with vinegar?

Yes, it is. As a matter of fact, vinegar can be used to restore a dried brush to its original state. You simply need to place the vinegar in a pot and heat to boil. Then, dip your brush into the solution while it’s hot for about 20 minutes. After that, wash with warm, soapy water and remove the paint residue with our hand or a comb.



Clean water can be used to remove water-based poly, while oil-based poly necessitates the use of chemicals. But, brush combs are also wonderful option for cleaning both types of polyurethane from a brush, especially if you do finishing and painting work on a regular basis. These small tools make it easier to clean the brush precisely with less effort, and they can also be used for other sorts of finishes.

However, there is no need to clean the brush in between coats. You simply need to place your brush in a plastic bag and place it in the refrigerator for a few hours. This will help keep the brush in a good working order whenever it’s ready to be used. Overall, cleaning your polyurethane brush after each use is essential as it helps to keep it in good shape while giving it a long life span.