i really dislike using invisible thread on anything that is (use-able; washable)
i used invisible thread on my sons bed quilt...every time it is laundered a bit more of it breaks...disappears...there are POKEY places...where the broken thread sticks out and pokes you like those annoying tags in shirts that will drive you crazy. so, i am not a fan of using invisible (fish-line) thread. i would try it on a small item(like a pot holder) then launder it ...and see before using it on an item more important.