Nikwax Tech Wash is perfect for cleaning all your breathable waterproof fabrics, if the outer fabric of your waterproof gets dirty it can absorb water and the garment can lose up to 70% of its breathability. Nikwax Tech Wash is a non-detergent, biodegradable liquid soap that removes dirt and detergent residues, while leaving water-repellency intact. Use to clean all clothing before re-proofing breathability and water repellency.