Topband: Cleaning Up Large Air Variables?

[kd4e]

I bought a Dentron MT-3000/MFJ-984 from a Ham whom,
it turns out, lives near the Katrina-damaged area.
I made the mistake of not insisting on photos.

It arrived showing clear signs of being under water
for a while - he is unrepentant - MFJ reports several
problems from the area with flood-damaged gear.

I read the posts about cleaning a roller inductor
and wonder what would be the best way to clean the
air-variables.

Can they be immersed in some sort of cleaning solution
without harm to the ceramic, brass, and other metal?

I have to partially disassemble things anyhow to add
the switched-in 250 and 500pf dooknobs to improve
matching on 80 & 160M.

Also, the metering circuit board has rust and deposits,
is there a preffered material to clean it?

MFJ has orphaned the 984 so no replacement is available
for the board - I am guessing that Dentron parts are
also no longer available?

-- 

Thanks! & 73, doc, KD4E
Projects: ham-macguyver.bibleseven.com
Personal: bibleseven.com/kd4e.html