Rather than using 2 layers of denim, try using one layer of the silver teflon fabric (like they make ironing board covers from) on one side. My sister makes potholders by the hundreds (I'm not kidding -- I've got 100 sitting in two bags waiting to be given out at a retreat next March) and she uses the teflon fabric with cotton batting. I use two layers of fabric and the insulbright when I make table runners, which can then double as a long hot pad. My DH doesn't cook / grill / BBQ, but my son does. I may have to "borrow" your idea and all the little extras that have been suggested.