Can the stained Redwood be cleaned off?
Yes. If the stain is brownish, use a solution with Trisodium Phosphate (TSP), available at retail hardware stores. If the stain is black, use a solution with Oxalic Acid to clean the boards. This material is also available at retail hardware stores. Commercial cleaners are available as well. Identify the cause of the stain to ensure you choose the correct product. Certain concrete cleaners are specifically formulated to clean wood extracts from patios, sidewalks, or other concrete structures.
