[quote=sewnsewer2]BEWARE!! The pen marks will disapear with heat, but if it gets cold (like up north), they will reappear!
Sounds like you could write a hidden message with one of the pens...Imagine....make a patchwork scarf for a child off on their own...it gets cold, suddenly a message appears on the scarf...."Wait, think, what would your mother say about this?"....Or maybe on a quilt.."Who loves you baby...Mom does" I think the fact that is appears in the cold could be used for added fun. As for quilts, mostly they are in the house where it is usually warm. I do not store many quilts in the freezer but if I do and the marks come back maybe a trip to the dryer or ironing board would teach it a lesson. I have these pens and use them with the same care as I would any other tool.