DEFY Wood Brightener is designed to be used after DEFY Wood Cleaner or DEFY Stain Stripper to neutralize the surface and restore the natural beauty of exterior wood. This product excels at removing rust or tannin stains caused by fallen leaves and is recommended for use on all species of wood, including redwood. DEFY Exterior Wood Brightener is an oxalic acid deck brightener that removes dirt, grime, tannin, rust, and fungi stains from wood surfaces. This liquid concentrate is mixed with water (four parts water to one part concentrate) to brighten and restore the natural beauty of exterior wood. DEFY Wood Brightener will not harm wood fibers, grass, or most plants when used properly. DEFY Wood Brightener is recommended for surface preparation prior to initial application of clear and semi-transparent finishes and stains. It is used as a neutralizer and brightener for all wood species that have been cleaned with DEFY Wood Cleaner or DEFY Wood Stain Stripper. For best results, use DEFY water repellent wood stain finishes.