It's a rare cabinet that can escape damage in the busy environment of a kitchen, so if you like your cabinets blemish-free, it's good to have some finish restoration smarts. Scratches, smudges and dings that haven't penetrated to the wood are easier to repair than those that have. Because the latter usually require sanding, it's easier to make the repairs if you take the affected door down and lay it flat on a worktable.
Minor Scratch Repair
Minor scratches to the finish are the easiest defects to handle on cabinet doors, as long as they haven't penetrated deeply into the wood or don't cut across the grain. Walnut oil is a natural wood preservative that can make scratches disappear, and to apply it, simply rub a raw walnut along the scratch. If you need something more robust, rub a dab of penetrating oil finish into the scratch with a rag after making sure the color is a good match. Furniture polish is a middle-path solution that, like walnut oil, you'll probably have to reapply periodically.
Fingerprints and Other Blotches
Cabinet doors, especially the ones that overhang sinks and food preparation areas, tend to develop dark areas around the areas that people most handle them. The darkness is often in the wax coating or the surface of the finish, and you may be able to wash it off. You can make your own wood-cleaning solution by mixing 2 tablespoons of turpentine and 4 tablespoons of boiled linseed oil in a gallon of very hot water. Use rubber gloves and a soft cloth to rub the affected surface. The solution removes old wax, greasy fingerprints and other stains without affecting the finish.
Rub It Off
Washing solutions don't remove deeply embedded dirt or stains that have penetrated the finish, but you may have success with an abrasive rubbing compound. To make a simple one, pour a small amount of pumice in a small bowl and some mineral oil in another. Dip a swab of 0000-grade steel wool first in the oil and then in the pumice and rub the affected area with it. When you're done with this treatment, you have to wax or polish the door, because rubbing down the finish in this way flattens the finish. This treatment also removes cloudy white moisture damage in the finish.
Deep Scratches and Dents
You can buy wood filler sticks -- somewhat like crayons -- that you can draw along a deep scratch in a wood surface to fill it. It's a time-saving solution for deep scratches and dents as long as the filler and wood colors match. When the defect is extensive enough to require sanding, you can often do a spot repair by sanding out the defect without the need for stripper. If you carefully feather the edges of the repair with the sandpaper, the stain and finish you apply to cover it will blend into the existing finish more easily. Cabinet doors are usually lacquered, and you can spray lacquer from a can. Use three coats, sanding each undercoat with 320-sandpaper before applying the next.