A waterproof that has stopped working has usually not failed - it has got dirty. Body oils, smoke and mud sit on the face fabric, the surface wets out, and the membrane stops breathing long before it stops being waterproof. Washing it is the first fix, not the last resort.
The order matters. Nikwax Tech Wash first, as a cleaner that does not leave the detergent residue an ordinary wash powder does. Then reproof: TX.Direct for membrane shells, wash-in for whole garments or spray-on when you only want the outer treated and not the lining. Polar Proof does the same job for fleece, Cotton Proof for cotton and polycotton, and Nubuck & Suede Proof for boots and leather uppers. Tech Wash and TX.Direct are also sold as a bundle and in twin packs, which is the sensible way to buy if you are doing a season's worth of kit in one go.
Waxed cotton is a different job again and wants a wax, not a proofer - Hoggs of Fife waxed leather balm and wax cotton dressing in neutral, or the Storm spray-on dressing. Work it in warm, thin, and leave it overnight.
Related: footwear care · Nikwax · waterproof clothing
