Caliper carrier (bit the caliper slides in) is steel, so will rust. Look for rust converter liquid (acid-based) at a hardware shop. E.g. Kurust, Jenolite etc. Wire-brush caliper carrier using angle grinder or similar with wire brush attachment. Ideally leave the parts soaking in an ice-cream container full of the rust converter.
Paint with high-temp silver paint, aerosol cans are pretty cheap, they claim 1200 degrees F, should be enough for that carrier?
As for discs, just replace! Old ones probably too thin anyway - min. thickness about 6-7mm. Use copper grease to prevent rust where disc bolts to the hub. Just a smear, and check the disc runs true by holding a pencil etc. on the caliper carrier and turn the disc. If not true, unbolt and turn 90 degrees, try again.
1994 eh? - that's new by my standards! Here in salt-free New Zealand we have original discs on 1987 Unos, smooth and rust-free but worn wafer-thin... measured some on friend's Uno and they were 4mm - dangerous.
-Alex
'88 Uno Turbo i.e.
'87 Uno 60
'88 Bertone X1/9
'81 X1/9 1500
'92 Alfa Romeo 164 3.0V6
'03 Suzuki SJ50QT (!)
