Any wood surface with a polyurethane wood finish can develop scratches with normal wear and tear. You commonly see these on floors or tabletops with heavy use. Additionally, once the protective finish has been broken by a scratch, the wood underneath can be irreparably damaged by moisture or deepening of the scratch in the wood. So, it is best to repair scratches right away and keep the wood protected.
Step 1 - Determine the Type of Scratch
Examine the damage closely to see if it is shallow—only in the finish—or if it is a deep scratch that penetrates down into the wood below the finish. Each type will call for a different method to treat it.
Step 2 - Clean the Surface
Thoroughly clean the area to be treated. Be sure there is no dust on the surface.
Step 3 - Apply Wax
If the scratch is superficial then applying wax may help to level the surface and hide it. Use a soft cloth to put the wax on, and then buff it in the direction of the wood grain. Let it dry for a few minutes before you get a clean cloth to give it a final buffing.
Step 4 - Sand the Area
If the scratch is too deep to be fixed with wax then start sanding the area with a fine-grit sandpaper. Always sand with the grain of the wood, not against it, and use a light pressure. For a surface scratch, only rub over the area with fine steel wool instead of sandpaper.
Take a clean cloth afterward and spray it with water. Use it to wipe the area to remove any dust that resulted from sanding. Let the area dry completely before continuing.
Step 5 - Stain the Wood
To disguise the scratch further, take a wood filler stick or a wood marker to it. Be sure to match the color of the stick or marker as closely as possible to the wood itself to achieve the best results.
Step 6 - Apply a New Spot of Finish
Take an artist’s brush and dip it into a can of polyurethane. Tap it on a paper towel to remove any excess, as this will aid you in applying a thin coat that will blend in better with the rest of the finish.
Apply the polyurethane to the scratched areas, and then let it dry for 24 hours. Add as many coats as needed to level the scratched area with the surface. Let each coat dry between applications, but it's not necessary to let them sit as long as the first.
Learning to repair scratches on your own will keep you from having to hire a professional and save you money on refinishing bills. Knowing how to do it yourself will also help you be able take care of tiny scratches you notice right away so they don't grow worse. Additionally, don't forget that regular maintenance is the best way to protect your finished wood and keep it looking beautiful.