[srbby]

Staples can't be microwaved. Yes I know, you can microwave the cup and then put the bags in, but some people make that mistake and (rightly) freak out when they see the fireworks.

[markrages]

Staples microwave OK. A microwave's wavelength is about 12 cm. A staple is a small fraction of that and won't couple much energy.

[vonmoltke]

Not to mention the water it is submerged in absorbs the actual radiation, so it generally doesn't even make it to the staple to begin with (at least, if you push the bad down to flood it before heating).

[okcando]

Surprisingly, you can microwave a stapled tea bag that's submerged in water.

You can also get away with microwaving metal spoons but _not forks_.

[windsurfer]

Would there not only be a buzzing sound and lots of bubbles? I doubt there would be any sparks if the metal is submerged in water.