i wouldn't use anything that roughs it up, like toothpaste. i'd go right to bleach on a q-tip, as said. if you have time, wash again with retayne. if you can't find it, use a color catcher. for new quilts, retayne is always a good idea before an accident occurs. this is why many quilters wash all fabric first. i wash first and always with retayne. why take a chance?