To clean water stains from wood, determine if the water has stained the finish or the wood. To remove water stains from the finish, use heat or oily materials over the stain. To remove water stains from wood, remove the finish and scrub with water and soap or bleach.
Water that has stained the finish lends a milky or cloudy appearance to the surface. To remove this stain, simply replace the moisture with an oil. To do this, apply mayonnaise, lemon oil or petroleum jelly over the surface using a spatula and leave for a few hours or overnight. Wipe the oil layer with a soft damp cloth.
Alternatively, expose the stained area of the wooden surface to heat from a hair dryer. This steams the moisture away from the surface.
Water that has stained the wood causes it to become dark or black, resembling mold growth. To remove this stain, scrape away the finish using 120-grit sandpaper. Scrub the exposed wood gently with water and soap to get rid of the discoloration.
If the wood remains discolored, use an oxalic-acid bleach. Use a ready-mixed bleach or mix one yourself. Coat the bleach solution on the exposed wood, allow it to dry, and vacuum the area. Then, wipe a solution of baking soda and water over the area to remove the acid. Finally, rinse with water, allow the wood to dry, and reapply the finish.