..and I didn't even know this was possible. I was broiling some cut tomatoes on a baking sheet lined with a Silpat that didn't quite fit (it was longer and thinner than my baking sheet) and, a corner of it accidently came into contact with the heating element when I turned the sheet halfway though cooking..
When I opened the oven a few minutes later, some white ashes flew out, and I noticed they were from the now-burnt-off corner of the Silpat. Thankfully, none of them landed on the tomatoes.
I thought Silpats were pretty much fireproof, at least at home cooking temperatures. Exactly how much abuse can these things take??