I have recently acquired a model M0116 keyboard (the compact mechanical version from the late '80s). It's in great condition overall, and I've just spent a couple of hours cleaning all the plastics. 

However, one of the keys is unreliable and I find myself missing that letter from time to time when typing.

Anyone got any ideas? Will a blast of compressed air sort it out, or is the switch likely on the way out? I was under the impression the Salmon Alps switches were rated for tens of millions of actuations.