Does Polyurethane Get Dirty? How to Restore

Planning to add polyurethane coating on your next woodworking project but not sure if it can handle spills and dirt?

Yes, polyurethane does get dirty when not maintained properly. Generally, minor spills and dust can be easily cleaned from the surface by using a clean cloth and water. However, stubborn stains and UV-damaged finish can require sanding to remove the previous coating before applying a new coat.

We tested a polyurethane finish on wood by subjecting it to several conditions and prepared a detailed guide on maintaining a polyurethane finish.

How Does Polyurethane Get Dirty?

Stain produced by a spill over PU coated workpiece
Stain produced by a spill over PU coated workpiece

Polyurethane is strong and can keep out water, scratches, and other damage, but it can still get dirty and stained from food, drinks, and other liquids spills.

Dust and pet hair can also stick to polyurethane surfaces, making them look dull and dirty.

Also, over time, polyurethane can get sun damage, causing it to change its color and fade.

How much dirt and stains polyurethane gets can depend on the weather, how much it is used, and what type of polyurethane it is.

For example, polyurethane used in busy places or outside may get more dirt and stains than those used in quiet indoor places.

Also, oil-based polyurethane tends to get dirty faster than water-based poly.

How to Clean and Restore Polyurethane

There are primarily three main causes of a dirty polyurethane finish: stains, dirt, and UV damage.

How to Clean Stains Off Polyurethane

Using a wet cloth to rub and remove the stain
Using mild detergent and a clean cloth to rub and remove the stain

Polyurethane can get stained from spills or accidents.

To clean stains from polyurethane, do this:

  • Use a clean, dry cloth to soak up the liquid or stain as much as you can.
  • When the surface is dry, put some mild soap or polyurethane cleaner on the stain and rub it with a soft brush or sponge.
  • Wash the area well with clean water and dry it with a soft towel.

If the stain is still there, you can try this:

  • Mix vinegar and water in equal parts.
  • Put the mixture on the stain and wait for a few minutes before rubbing it gently with a brush, sponge, or damp cloth.
  • Wash the area well with clean water and dry it with a soft towel.

How to Clean Dirt from Polyurethane?

Using a brush to dust the polyurethane finish
Using a brush to dust the polyurethane finish

Dirt and dust can accumulate on polyurethane surfaces over time, leaving them looking dull and dingy.

To clean dirt from polyurethane, start by wiping the surface down with a soft, dry cloth to remove any loose dirt or debris.

Then, mix a few drops of dish soap or another gentle cleaner with warm water and gently scrub the surface with a soft cloth or sponge.

Rinse thoroughly with clean water and dry with a soft towel.

If the dirt is particularly stubborn, you can try using a specialized polyurethane cleaner.

How to Remove Yellowing Due to Sunlight?

Sanding the yellowed PU finish before applying fresh coat
Sanding the yellowed PU finish before applying fresh coat

Sunlight can make polyurethane turn yellow. You can’t clean or wipe off the yellow color, so you need to fix the finish.

To make the polyurethane-finished workpiece look new again, you need to take off the yellowed polyurethane coating and put on a new one.

You can use a sander and rough sandpaper to sand off the PU coating from the workpiece.

When the old coating is gone, clean the workpiece to get rid of any dust or dirt.

After cleaning it, you can put on new coats of polyurethane and make the workpiece look good again.

Things You Can Do to Prevent Polyurethane from Getting Dirty

Polyurethane coated workpiece with dust over it
Polyurethane-coated workpiece with dust over it

Cleaning polyurethane surfaces keeps them last longer and look better, but it’s also good to stop them from getting dirty in the first place.

Here are some things you can do to keep your polyurethane surfaces clean:

Use Coasters and Placemats

Using coasters and placemats is a simple way to keep polyurethane surfaces clean.

They can keep surfaces safe from spills and stains from drinks, food, or other liquids.

Make sure to use coasters and placemats that are easy to clean and work well for polyurethane surfaces.

Keep Out of Sunlight

Sunlight can make polyurethane surfaces change color or fade over time.

To stop this from happening, keep your polyurethane surfaces away from sunlight as much as possible.

If you have polyurethane furniture, use curtains or blinds to block the sun when it is very hot.

Clean Spills Right Away

When spills or accidents happen, clean them right away.

Use a clean, dry cloth or paper towel to soak up as much of the spill as you can, then clean the area with some mild soap and water.

The more a spill stays on a polyurethane surface, the more likely it is to make a stain or mark.

Use Protective Pads

Polyurethane-finished wood floors can get scratched by heavy furniture.

These scratches might be small, but they can hold dirt and stains, making the polyurethane finish dirty.

So, it’s good to use pads or felt on the bottom of the legs to stop scratches or damage to the surface.

You can also use pads on the bottom of lamps, vases, or other things to stop them from scratching the surface.

Final Thoughts

Polyurethane finish is prone to moisture and scratching but can get dirty by spills and dust.

A liquid spilled over the polyurethane finish can leave stains that can be cleaned using a clean cloth and soap.

However, you can also use special cleaning chemicals or vinegar to clean stubborn stains.

Similarly, to clean dust and dirt from a polyurethane finish, dusting the surface to remove any abrasive materials, then cleaning with soapy water.

You Might Also Enjoy

Frequently Asked Questions (FAQ)

Can you clean oil stains from polyurethane?

Yes, you can clean oil stains from a polyurethane finish by using a clean cloth and soapy water.

Does polyurethane get stained by water?

No, polyurethane does not stain with water. However, soaking the workpiece in water for a prolonged duration can cause water stains and even damage the polyurethane finish.

Can you apply a fresh coat to remove stains from the polyurethane finish?

Yes, you can apply a new coat to remove stains from the polyurethane finish. However, it is important to to sand and remove the stained coating underneath before applying a new coat.