How To Clean White Rings from Wood
White rings from cups, vases and other vessels are a form of water damage. Water gets into the finish and causes what is also referred to as a blooming effect, a milky colored stain. This kind of damage can occur even without a spill, from condensation. Whitish discoloration indicates that the moisture has penetrated the finish but has not yet damaged the wood. The rings can be treated simply, although multiple steps may be required to fully restore the appearance of the finish. Since types of wood and wood finishes can vary any material or method should be tested in an inconspicuous spot before being used in a wider area.
First, clear your work area, and make sure that the surface is free of any objects such as vases, glasses, books, papers etc. Lightly dust with a soft dry, cloth to remove loose debris. Next, address the white rings. Take a soft, clean cloth, and dampen it lightly with denatured alcohol. Keep in mind that denatured alcohol and rubbing alcohol (which, now is largely made of isopropyl alcohol) may not have the same effect. Wipe the ringed or otherwise watermarked area lightly with the barely dampened rag. Repeat as necessary. For very precise application you can substitute a cotton swab for the clean rag.
If the water rings and marks were particularly severe, or if they were treated with an excessive amount of denatured alcohol, you may wish to do a little touch up work to help fully restore the overall finish. After applying paste waxes or other finishes, keep in mind that even if the surface is dry to the touch, it may be a good idea to let the surface rest undisturbed overnight before using it or placing any objects on it.
To restore a lustrous finish, rub with a paste wax designed for satin finishes and a 0000(extra fine) steel wool. Read the ingredients in the paste wax, and avoid products with potentially damaging additives such as silicone, xylene or toluene.
For gloss finishes, perform a touch up to the affected area, and a little bit of the perimeter around the stain using a soft buffing cloth and auto polishing compound.
To prevent subsequent damage, use protective coasters and mats for beverage/food service and vases. For plants, remember that a protective dish may not be enough. The plant and dish should be elevated on a dry stand so that air can circulate underneath and prevent damaging trapping of moisture.
Caution: Never mix cleaning agents or chemicals, the result can be dangerous or deadly. Before cleaning, always test the agent on an inconspicuous location to determine its suitability and to make certain it does not damage the material. Wear appropriate clothing such as gloves and protective eyewear, and work in a well-ventilated area. Accidental inhalation or ingestion of cleaning agents can be hazardous and even fatal, particularly to pets and children.