Remove water marks from wood by ironing or by applying mayonnaise. The procedure varies with the type of method you apply. Additionally, the sooner you remove the marks, the easier the work and the better the results.
To iron the marks, start by preheating the iron on warm mode. Once the iron is ready, cover the water mark with a cloth napkin, and iron the mark through the napkin in cycles, allowing an interval of 20 to 30 seconds between the cycles. Each cycle should take five to 10 seconds. Be sure to buff the wood after every three cycles. In case of unfinished wood, sand the surface lightly with a fine-grit sandpaper or apply a solution of water and mild detergent to render the stain loose before ironing.
To use mayonnaise, first measure 2 tablespoons of the mayonnaise, and spread it on a paper towel. Set the paper with the mayonnaise over the mark, and apply light pressure. Allow the mayonnaise to sit on the mark for quarter an hour before checking the mark. Rub any mark remnants with mayonnaise, and repeat the process as needed until the mark disappears. For an older mark, allow the mayonnaise to sit on it overnight for better results.