Because it leaves no detergent residue, using Nikwax Tech Wash for all cleaning of your waterproof-breathable garments will help get the longest possible life from the factory applied DWR (Durable Water Repellency). Tech Wash is also excellent for pre-washing items before applying Nikwax TX-Direct, and other Nikwax treatments such as Polar Proof, Down Proof, or repellency restorers from other manufacturers. It can be added to a load in the washing machine or applied directly for spot treatment of grease and stains. Non-detergent. Biodegradable.