How to Clean Polyurethane

If you buy something through a link in our posts, we may get a small share of the sale.

Are you finding it difficult to clean your polyurethane panels? While it can a tricky process, it is important that you understand how to clean it without messing the whole project. If you don’t know how to go about this, this guide on how to clean polyurethane panels will set you on the right path.

How to Clean Polyurethane

There are two instances when you need to clean polyurethane. 

  • Cleaning polyurethane from your brush and tools when you finish the painting 
  • Cleaning a surface that has polyurethane 

These instances prove to be tricky at times, as with simple mistakes, you can mess up the whole project.

Man about to clean polyurethane from wood

How to Clean a Polyurethane Finished Wood Panel

This process involves cleaning the finish, not the wood. So it would help if you used cleaning agents that are suitable for such coating. Remember, we’re looking to gently clean it, not actually remove the polyurethane from the wood!

The method you choose to use depends on your cleaning circumstance. These circumstances include removing dust, stain grease, or grime. 

We recommend that before starting the cleaning process, you ensure you are dealing with polyurethane correctly by doing some tests. This is because while some finishes look like polyurethane, they will react to certain cleaning detergents that the real polyurethane won’t.

Be sure you know the differences between other wood finishes like polycrylic so that you don’t accidentally choose an incorrect cleaning method.

How to Test

Rub some drops of boiled linseed oil on the surface. You know that it is a hard finish to oil-based when it beads up.

The second way you can test it is by rubbing acetone on the surface in a circular motion. Choose inconspicuous spots for this test so that it will be hard to notice when it reacts with the wood.

Polyurethane repels acetone and will bead up like water. Acetone substance is available in regular nail polish.

How to Dust Clean Polyurethane Surface

You can always keep your polyurethane wood panel dusted with a dry microfiber cloth. Use a stiff nylon brush for too dusty areas or surfaces that have accumulated mountains of dust. Brush along the wood surfaces’ groves and use short strokes to get rid of the dust.

You can use a small toothbrush for crevices. Another way to remove dust is by using a vacuum cleaner with a brush.

Person holding a piece of wood

How to Clean Grease and Grime from Polyurethane Surfaces 

You can use a moist cloth to wipe away some grime, grease, and specks of dirt. However, with time and continued use, the wax accumulates, and the grime becomes more stubborn. So, you need more robust cleaning agents to keep your cabinet, furniture, or floor clean.

There are two types of cleaners you can use for this purpose: 

  • Mineral spirits 
  • Vinegar

Using Mineral Spirits or Rubbing Alcohol

When using mineral spirits, dump a clean, soft rug or towel in it and wipe your surface clean. This will help remove the dirt and the stubborn greasy marks on your wood surface.

You can also use rubbing alcohol in the same way. It works better, especially around doorknobs and smaller surfaces.

Using Vinegar

You can also mix water and vinegar in a spray bottle to remove the greasy marks from your wood. Vinegar is a soft cleaner that will break up the grease. It does not damage or cause any abrasion to your polyurethane.

Another good thing with vinegar is that it works like glass cleaners. Thus unlike other detergents, it will not cloud the polyurethane finish.

How to Remove Stains from Polyurethane Surface

Using a microfiber sponge is one of the most effective ways to remove stains. It works with permanent markers and any other types of stains.

Some stubborn stains will discolor your wood surface. When this happens, use fine-grit sandpaper for sanding the stained region. Then use a cloth to wipe the dust and apply a new coat of polyurethane. Just be sure that you don’t sand the stained wood too aggressively and remove part of the stain.

Helpful Tips on Cleaning Your Polyurethane Finish

Similar to polycrylic, a polyurethane finish protects your wood surface and gives it a beautiful, elegant look. If you are reckless while you clean it, you may weaken it and damage it. Below are some of the crucial tips that will help you care for your polyurethane wood panel.

Man wiping the wood clean off of polyurethane

Do Regular Cleaning

Regular cleaning is the best way to maintain the color and texture of your surface. You can always use a soft-bristled brush or you can use a hand-held vacuum cleaner with hose attachments.

In places like kitchen cabinets, your panel is likely to get greased. In this case, apply robust methods like using mineral spirits or vinegar, as explained above. You can also go for commercial cleaning solutions.

We recommend that before you apply any detergent on the wood surface, read the product label. It will help you determine the designated products that are safe for such purposes.

Use Moderate Water

As much as you have to use water in your routine cleaning, excess usage can damage the polyurethane. Polyurethane is sensitive to water saturation. So, only clean it with a damp piece of cloth instead of soaking it.

You can scrub the stubborn stains with the damp cloth and immediately dry it with a dry soft towel.

Apply Only pH Neutral Cleaners

Polyurethane is also sensitive to extreme alkalinity. Always ensure that the cleaners have the label “pH neutral cleaner” or “neutral cleaner.” If you can’t get the right product, you can consult an expert for more directions. 

Such products are safe for both oil-based and water-based polyurethane finishes. If you’re looking for other water-based finishes, you can also consider using lacquer.

Avoid Wax Coating

Avoid using any wax coating, oil soaps, and any cleaners containing ammonia at all costs. They are abrasive and can damage the coating. We recommend using dry methods, damp cloths, and approved commercial cleaners instead.

How to Clean Polyurethane From Your Paintbrush

After applying polyurethane on your wood surface, you must clean your brush.  The method you use will depend on the type of polyurethane you used. To be sure of the type of polyurethane you are dealing with, please read the packaging’s back.

Method One: Cleaning Water-Based Polyurethane from Your Brush

Water-based polyurethane is the easiest to clean off your brush. You only need to soak your brush in a container of water after you finish painting. You will need two or three ups to rinse the brush and ensure that it is sparkling clean.

Method Two: Cleaning Oil-Based Polyurethane from Your Brush

Cleaning oil-based polyurethane from a brush is more demanding. You can follow the following simple steps to do it. 

What you need

  • Paint thinner
  • Lukewarm Water
  • Regular dish soap
  • Mask
  • Gloves
Man mixing a can of polyurethane

Step One: Protect Yourself

Oil-based polyurethane and paint thinner contain harmful chemicals. As always, we recommend you wear protective face masks and hand gloves at all times. We also recommend that you have proper ventilation in your workspace and keep all the windows and doors open.

Step Two: Pour the Thinner into a Cap

Fill three quarters of the container or cup with paint thinner. It would help if you did not fill it to the top to cut spillage due to constant shaking and stirring. You can always add more thinner to the container or replace it with a bigger one when the need arises.

Step Three: Dip the Brush into The Paint Thinner

Dip your brush in the cap (with paint thinner) and leave it for about 15 to 20 minutes. The duration will allow the thinner to penetrate polyurethane between the bristles.

Ensure that the thinner level gets to the metal part of the brush to prevent it from hardening up. Also, do not jam it straight down the cap; bend it side to side.

Step Four: Wring Your Brush

Wring out the brush until the paint thinner becomes clean and then remove it.

Step Five: Wash Out the Thinner

Go to your sink and pour dish soap on the brush, working it on the bristles to get to the hidden polyurethane.

Rinse the brush with lukewarm water.  Using hot water on your brush may loosen the glue that holds the bristles, causing them to fall off. You should also avoid using cold water as it may cause the brush bristles to harden.

After rinsing, rub the bristles against your hands (with the gloves on). If it lathers up, you are good to go.

Step Six: Dry Your Brush

When you are confident that your brush is clean, dry it to prevent the bristles from hardening. Wipe the brush with an old piece of clothing or towel until it no longer drips.  Air it for a moment and then store it in a safe place for your next project.

Alternative Methods

Instead of paint thinner, you can also use turpentine or mineral spirits. You have to read the instructions behind the container for more directions.

The whole process seems simple as you only need to dip your brush in different mineral spirits caps. It would help if you did this until the last one remains clear.

You also use regular soap and water to wash your paintbrush. Yet, this method involves a lot of work and is less effective. You only need to go to the sink, apply the dish soaps on the bristles, and wash it off until it stops to leather.

Conclusion

Polyurethane requires great attention during and after application. You must use the right tools and processes to ensure.  You must also ensure that the tools you use in applying the polyurethane are clean.

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.