I love Frixion pens! Actually, I like the fact that cold brings them back. I am doing Redwork embroidery on quilt blocks. I read here that Redwork works better with a lining. I trace the design on the fabric with a black Frixion pen, then iron a sheer interfacing to the back. Of course my design disappears. I put the block in the freezer and my design is back. With the interfacing added before tracing the design, the design is much more difficult to trace. Since I am embroidering over the lines, they would not show even if they did come back. I also use the pens on my quilts and have never had a problem. I use only black and usually test it on a sample of the fabric before using.