[OT] how to clean grime off old computer MB?

["Douglas A. Tutty" <dtutty@porchlight.ca>]

Hello all,

I have a couple of new-to-me old computers.  They've been well used in
what looks like a normal office environment and they're a bit grimey
inside; not just dust that blows away.  I figure that I should clean
that off so the dust doesn't act like a thermal insulator but I'm unsure
what to use, since air alone isn't doing it.  I don't want to remove
e.g. the CPU from its socket. (P-133, socket 7).

What have you used sucessfully?

This is at home so I'm not set up for, e.g. a chemical bath.  

Doug.