How to Use Oxalic Acid to Remove Wood Stain

Wood floors and furnishings are available in a wide variety of hues, from natural pine to dark mahogany or Brazilian cherry. When refinishing furniture, homeowners may also choose to lighten or darken the piece's color. Before attempting to bleach the stain, though, remove all finishes with a solvent-based stripper. Sanding, according to the University of Kentucky Extension is the preferred method for stripping wood flooring, but this process removes too much of the grain and may cause damage to furniture.

• 1

  Spread a drop cloth or newspapers on the floor to protect surfaces. Don rubber gloves and eye wear, because oxalic acid is corrosive.

• 2

  Mix 5 oz. oxalic acid with 1 gallon water in a bucket. Spread the mixture on the entire surface with a paint brush or rag, coating it well. Wait 20 minutes.

• 3

  Apply more bleach solution and wait 10 minutes more until the wood is the original color. Repeat the procedure if necessary to lighten it further.

• 4

  Mix 1 tbsp. clear ammonia with 1 qt. warm water in a bowl or jar. Brush or rub this mixture on the wood to neutralize the bleaching action.

• 5

  Wipe the surface with a damp cloth to rinse off all cleaning solutions. Dry the surface with a clean cloth.

• 6

  Wait 24 hours for the wood to dry thoroughly. Sand the wood to remove any raised grain before applying a new finish.