I recently used a purple kid's washable marker on a quilt and freaked when it didn't "wipe off." I wrote on this board to ask opinions. What I ended up doing was washing it before attaching the binding, (zig zag edges first)and with no detergent in cold water. It came right out!!!! JUST DO NOT IRON FIRST. I'm a newbie to FMQ and need dark clear lines to feel comfortable, so mark away!