Oxalic acid was used extensively as a bleach before two-part bleaches were developed. It is not as strong as the newer bleaches, but the wood tends to retain more of its character after bleaching with oxalic acid. To be used as a bleach it must be dissolved in hot water and used hot. Usually a saturated solution is used. It is made by dissolving oxalic acid in hot water until no more will dissolve and some is left undissolved. Apply the hot solution with a nylon brush. When the desired amount bleaching has taken place, wash the area with water. The last step is to wash the area with a solution of three ounces of borax mixed with one gallon of water.