When I started mine, I found something (Maybe on the insulbrite package) that said to sandwich 1 layer of insulbrite between 2 layers of warm & Natural. Also, to use only cotton thread as the poly can melt and burn you. I thought it was kind of odd then that there is poly in the insulbrite, but its between the cotton and fabric on mine and the only time I've gotten heat is if it gets wet and I keep trying to use it.