Originally Posted by
ai731
Our guild uses the Frixeon (sp?) pens. Like one of the above posters said, test first. Our experience is that they "fade" really well on light-coloured fabrics, but on very dark fabrics they seem to leave a white-ish or silvery line behind (that's with ironing - I don't know what happens if you just leave it to fade with time, or wash it).
The bright pink Frixion pen that I used this afternoon on a med. blue fabric left a white line when it was ironed. It didn't matter on the project I was working on because it was hidden. Always test on your fabric before using it in a quilt.