Before marking a quilt top with a Frixion pen for some finishing-touches-redwor, I marked some of the scraps from the top with the pen I intended to use. First I pressed the scraps with a very hot iron. All marks disappeared instantly. Then I folded the scrap and put it in the freezer compartment of the refrigerator. The marks reappeared. I put the scrap on an outside table in the hot Texas sun and the marks disappeared. Since it is much more likely that my quilt will be exposed to heat than to freezing temperatures, I marked the redwork pattern on the quilt top. It was a difficult task because the Frixion pen does not have the marking power that Sharpies have. But that difficulty is offset by the fact that the Frixion ink did not bleed into the surrounding fabric.
It is my opinion, which in this case is neither humble nor arrogant, that should the marks ever reappear because the quilt is exposed to freezing temperatures, the user huddled under it will not be very interested in the marks. froggyintexas