How to Remove Redwood Stains from Car Paint

by Robert Howard
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Redwood is a type of tree notorious for containing high levels of tannin. This is a naturally occurring acid that protects the living tree, but it can cause dark, unsightly staining, and redwoods tend to drop a lot of it. A car parked underneath redwood trees can end up with dark, unsightly tannin stains. With the right product, however, tannin stains are really easy to remove.

Choosing a rust-removal product

Step 1

Oxalic acid is the active ingredient in a variety of tannin removal products. It is sold as a liquid concentrate, as a premixed gel, or as a powder that can be mixed with water. Select the product that fits the scope of your project and your budget. For a large area, you may want to go with a powder or concrentrate; and if you are just focusing on a small area, a premixed gel or spray bottle application may suit your needs.

Step 2

Wet down the stained surface. Oxalic acid-based tannin removers are effective so long as the product is wet. If allowed to dry out, the oxalic acid become inert. It can be re-activated by misting with water. Apply the rust remover according to the manufacturer's instructions.

Step 3

Allow the product to sit on the stained surface. Typically tannin removers take between 15 and 30 minutes to completely neutralize and remove tannin stains. There is no need to scrub; oxalic acid chemically reacts with the tannins and neutralizes them.

Rinse the car down thoroughly with water. You should see the tannin stains wash right away with the water.


  • Oxalic acid is also a great rust stain-removal product, and it can be used to brighten up woodwork that has darkened as a result of tannin staining. Oxalic acid is often sold as a "wood brightener."


  • Oxalic acid is corrosive and can be absorbed into the skin, causing damage to the kidneys. Wear protective clothing, rubber gloves, and protective eye-wear when using oxalic acid-based cleaners.

Items you will need

  • Oxalic acid-based rust-removal product
  • Paintbrush, paint roller, or sprayer
  • Rubber gloves
  • Protective eyewear
  • Protective clothing

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