The effectiveness of any fabrics DWR Durable Water Repellent finish is maximized by proper cleaning. Nikwax Tech Wash 169 fl.oz. is a non-detergent, biodegradable cleaner that protects the water-repellent finish on fabrics by removing water-attracting dirt, contaminants and detergent residues. When you wash garments in Tech Wash, NIKWAX waterproofing treatments last twice as long as they will when you wash with detergent soap. The highly effective cleaning agents in Tech Wash and its ability to rinse residue-free improve the performance of virtually anything made of fabric, fleece or synthetic insulation.