How to Remove Grey From Wood

By David Sandoval

Many wood structures, such as decks and porches, will turn gray after being exposed to the elements for a long period of time. Gray discoloration can be caused by exposure to dirt, ultraviolet rays and mildew. To remove this gray color from a wood structure, it is necessary to wash the wood with specific detergent agents and to use caution when removing dirt and damaged wood surfaces. When this wood is treated and cleaned properly, the wood structure’s previous natural beauty can be restored.

List of Items Needed

  • Wood deck detergent containing oxalic acid
  • Water
  • Plastic bucket
  • Deck scrub brush
  • Power washer
  1. Add wood deck detergent containing oxalic acid to water in the plastic bucket to make a cleaning solution. Use the formula on the wood deck detergent container to determine the proper mixing ratio. Stir the solution using the head of the deck scrub brush.

  2. Scrub a small portion of the wood structure that has turned gray to verify that the detergent will not discolor the wood. For best results, scrub an area that will not be noticed as easily if the wood discolors. If the wood does not discolor, proceed to the next step. If the wood discolors after a minor scrubbing, wash the affected area with the power washer and skip ahead to Step 4.

  3. Immerse the bristles on the head of the deck scrub brush and gently scrub the affected areas of the wood structure. Once you are finished scrubbing the affected areas of the wood structure, you may dispose of the cleaning solution in the bucket according to the instructions on the wood deck detergent container.

  4. Wash the scrubbed areas of the wood structure by using the power washer. Firmly hold the power washer nozzle a few inches away from the surface of the wood structure until the gray color is washed out completely.

Tips and Warnings

  • Oxalic acid is harmful to plants. If the wooden structure is close to vegetation, cover this vegetation with a tarp or with plastic landscaping sheets before starting this project.
  • Since power washers create a high-pressure stream of water at the nozzle, take care not to point the nozzle towards yourself, other persons or pets. This water can be injected into your skin with great force and can cause painful injury.

© Demand Media 2011