I personally love fray check, but I only use it to prevent ravels, button holes from coming undone, etc....If you read the bottle it says it is permanent, but softens to the touch once you wash the item. I do feel it becomes *invisible* after washing, but I have not ever put it anywhere were it would be on an outfit that would *rub* all the time & possibly irritate. I wouldn't put it on a seem you plan to stitch through later with top-stitching or quilting. I'm sure it would be very difficult to get through. DO make sure it is completely DRY before you use or wash!