I have used insulbrite with a layer of cotton batting and it works well, I have also used a layer of an old cotton towel with a layer of cotton batting and it works just as well. I also make my potholders bigger so they can be folded in half for extra hot pots. Depends on what I have around when I get the itch to make potholders. I have been known to get towels from the thrift shop to reuse for innards.