Dear Adam and Jamie. I was just wondering (in the middle of the night when my wife and kids were asleep already) that could an hand grenade explode if you`d put it in a microwave oven for a long time?

That could come in handy - for example if an old lady wants to blow up her house but the pin is too tight.

The classic pineapple grenades were metallic, so a microwave would probably not be able to heat it up. Since the charge is inside the metal, it's likely the shell would shield it from the energy.

Old ladies in your area have access to hand grenades and want to blow up their own houses? Wow, now THAT'S a tough neighborhood!