The effectiveness of any fabric's DWR (Durable H2O Repellent) Complete is maximized by proper cleaning. Nikwax Tech Wash (169 fl.oz.) is a non-detergent, biodegradable cleaner that Safe guards the H2O-repellent Complete on fabrics by removing H2O-attracting dirt, contaminants and detergent residues. When you wash garments in Tech Wash, NIKWAX H2Oproofing 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.