Yeah,let
s start with the bascis here, what fabric, and how worn? Does it seem to have any peeling on the underside? I've used NikWax, Camp Dry, and Tectron WPers; and they all work best with certain fabrics. Tectron's really durable and my go to waterproofer. You need a dry, windless day to spray it down, or a garge to hang it in and leave the door up until it dries.