Found in a can of "Mexican spicy peanuts" from Thailand, one of those little packets of dessicant. As well as the usual "Do not eat" notice, it also says "Do not microwave". Talk about red rag to a bull! Now I wanna know what happens when you microwave this sucker.
Answers through my contact form and I'll post them here. Make it fast or this contract I'm on might come to a short, sharp end when I blow up the staff microwave.
Update 10 Oct 2006, 17:10 AEST
I've microwaved silica before with no ill-effect. It should be done with a glass of water alongside as there isn't enough liquid in the sachet to absorb all of the microwave energy. The reason for the warning may be due to that, orto discourage the idea that they are reusable, or because they contain something more sinister that really shouldn't be microwaved. Whatever the reason, if you try it, I'd suggest a glass of water on the side, and don't inhale. :p
Well Roger may be onto something, assuming it's Silica Gel... Seems some of them add indicator chemicals, which could be nasty. Though why they would add them to a closed, sealed container is anyone's guess.