I think the freezer test sounded funny too, who would worry about that? Nice to know just reironing the mark would make it disappear again, or even washing out the quilt once you finish it, which alot of quilters do anyway, would remove it. So, I for one, see no problem using these pens & plan to give mine a try.... Even the guy at Staples, who led us to them, when he asked what we were looking for, when I told what I wanted to use them for, understand totally, & being they are eraseable, could understand why they would work great...