I accidentally used the Frixon pens on my Steam a Seam Lite 2 and ironed them and all my markings were gone and I was so upset, thinking I had to redo them all. I wrote about this on the board and someone smartly wrote me to stick them in the freezer. I did and all the markings came back and I was able to cut them all out. So, they have a second purpose. I will try and never use them for appliqueing again, but if I accidentally do, I know how to fix it.