[redler]

> The key mechanism seems to be VERY robust and can take a lot of pounding. Usually the particles jamming the mechanism (e.g. food crumbs) can be broken up by repeatedly banging hard on the offending key.

I've done something similar by holding the base of an electric toothbrush against a misbehaving key that couldn't be cleared by some other technique. The high-frequency vibrations seem to do a decent job of breaking up or dislodging whatever's stuck.