I am just putting this out for your consideration. Although the Frixion pens will disappear with heat, it has been reported that the markings return if the fabric is exposed to extreme cold. Some stories have told of competition quilts arriving with the marking showing because the quilt(s) were in cold temperatures while being transported. Another concern with these marking is if the chemicals will eventually cause deterioration. They haven't been used long enough in quilting to determine this. These pens were recommend to me to mark a whole cloth quilt. However, I have decided not to use them because of these concerns.