I made several sets of pot cozies out of Reflex (Home Depot and the like) everyone always says that it's aluminum but it's not these things are normally Mylar over a plastic base. My point is that hot pans can melt plastic and Mylar.

Mine still works it just has less of the reflective coating on the inside then it did before. I also uses a flexible (plastic) reflective tape from the HVAC department on the first batch. The second set I used a foil (metal) tape but have not had a chance to use those pans yet. I also pack the cozies with the pans, it seems like the best way for my gear.

I have seen several made out of blue pad material, but that seems like a overkill to me, but it probably would retain the heat better. Again just be careful with the hot pots and pans, that stuff melts just as fast.

Wolfman