[GreenKeys] UGC-74A cleanup

[Jim Haynes]

I spent part of the afternoon trying a variety of harsh chemicals on a
gooey UGC-74A.  I haven't got into the printing unit yet - this was
just on the stuff that had dripped onto the case.

Denatured alcohol
Acetone
Mineral spirits
Non-flammable paint thinner
Gumout carburetor cleaner - but not the stuff that would be used on a
    workbench - rather the probably useless stuff you pour into the gas
    tank
Goo Gone
Oops! which is supposed to remove a lot of things including latex paint,
    but not oil paint

Of these the acetone seemed to work best for me.  But I didn't apply any
of them and let them soak, rather just saturated a paper towel and rubbed
with it.

Any comments?