Remove Redwood Stains from Car Paint
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.
Instructions
Choosing a rust-removal product
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.
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.
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.
4. Rinse the car down thoroughly with water. You should see the tannin stains wash right away with the water.
