Interesting post........I've used fray check a bunch making colorguard flags, it lasted on them, but they were never washed (did get rained on plenty ;) ). It did discolor some of the fabrics, made the edges darker and it's nearly impossible to put it on perfectly without blobs here and there. I have a phobia about raw edges, even on wallhangings that I can't seem to get over so I usually (always) avoid them.