If you have discoloration or scratches on wood furniture you are refinishing, it is important that you remove them. Fortunately, most problems can be repaired. Most wood furniture has a finish for protection. For this reason, only work to the depth that is affected, as you only want to remove the finish that you have to. In some cases, however, the only way to remove stains is to remove all the finish. Below are some tips on removing things like white spots, blushing, and black spots.
To remove white spots from your wood furniture, purchase a liquid furniture polish, and wipe it on the surface following the manufacturer's instructions. When you are finished polishing the white spot, buff the area using a buffing cloth. If this does not work, lightly wipe the area with denatured alcohol. Only use a small amount of the alcohol, as too much will damage the finish.
If you still see white spots on the furniture, you need to treat the area with abrasives. You can purchase gentle abrasives at most home supply stores. You can also make your own abrasive by mixing together four tablespoons of cigarette ashes with enough light mineral oil to make a paste. Rub the abrasive on the white spots along the grain of wood. Wipe the area clean with a soft cloth. Repeat this procedure again, if needed. If the spots are stubborn, you may have to do this several times.
When you are finished, wax and polish the surface of the furniture.
A white haze over a large area of the furniture is known as blushing. This is common with lacquer or shellac finishes. The white spots are caused by moisture.
Buff the surface of the stain evenly using steel wool that has been dipped in linseed oil. Wipe with the grain of the wood, and rub evenly on the surface until the white has disappeared. Wipe the area clean using a soft cloth, apply two coats of wood furniture wax, and buff the area until it shines.
If you have black spots on your wood furniture, water has penetrated the finish, and entered into the wood.
Sand the black spots to remove the finish. Put some bleach in a glass jar, dip an old brush in the bleach, and brush it on the spots. Let the bleach evaporate for two hours, apply more bleach in the same way, and let it sit for 24 hours.
If you still see the spots, use a commercial wood bleach. Moisten the area with a damp sponge before you apply this bleach so it can penetrate it better.
Mix the bleach following the manufacturer's instructions, and then brush it liberally onto the damp wood. Let it soak into the wood and it should start bubbling. Let it sit for four hours. After this time, you will need to neutralize the bleach. Mix two cups of water with one cup of vinegar. Dip a sponge in the mixture, and wipe over the black area. Once the black spots are gone, you will need to put the finish back on the wood. Purchase finish at a furniture store, and follow the manufacturer's instructions on how to apply it.
If you have problems removing any of these stains, take your wood furniture to a specialty furniture restoration company to remove them for you.