How to Fix a Cloudy Polyurethane Finish

Cloudy finishes appear for several reasons, including using an old product or one that's been stored in a very cold or hot environment. Proper application also requires stirring the polyurethane coating immediately before placing it on the surface, which should be clean and oil-free.

Close up of sandpaper
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Removing cloudiness may require sanding.

Step 1

Check that the polyurethane is completely dry, if you've refinished the piece recently.

Step 2

Clear out the work area, and turn off any open flames or pilot lights nearby.

Step 3

Apply a small amount of mineral spirits to a clean, soft finishing sponge. Wrap the sponge in a clean white cotton cloth. Twist the top to form a handle.

Step 4

Rub the wrapped sponge back and forth on the finish to remove about the first coat. Let it dry, then load a clean sponge and cloth, and repeat. Do this until you've removed the blotching and finish and are down to the stain. Let the surface dry completely.

Step 5

Lightly sand the piece with 220-grit sandpaper, if cloudiness persists. Sand until the polyurethane finish is removed. Reapply the finish per label directions, stirring the product as you work.

Emily Pate

Emily Pate holds a Bachelor of Arts in theater arts and government from New Mexico State University. She has worked as a dance and substitute teacher, administrative assistant and in film and videogame production. She has more than 16 years of theatrical experience as an actor, director and playwright.