Howdy Todd and Autumn,
Simple fix for grubby looking distributor: Easy solution is to wash the rusty parts with household vinegar (weak acetic acid) and it will turn ferrous parts black. Wipe them off and after dry spray them with either some urethane or Bostik Top Coat for Tool Surface Sealant (both are clear and will protect the ferrous surfaces without impeding the magnetic p/u or the reluctor function. Spraying the aluminum won't hurt a thing and also helps to keep down corrosion.
The rusty stuff is a result of the high energy sparking in the cap and that generates nitric oxide in the atmosphere within the cap. This is a reaction from ozone in the cap volume (from the duration and energy of the sparks in the cap). Need to check the phasing of the rotor to the cylinder poles. Air circulation will also help, the small breather on the cap is not enough so it helps to sometimes drill a 3/8" diameter hole in the bottom of the distributor. The vertical ribs on the rotor will function as an air pump and allow air movement within the cap which is a plus.
What you showed in your pic of the distributor is pretty common and although it looks ugly, is easy to fix.
Good Luck with the simple fix while you are waiting for other parts.
Regards,
HB2
Dissident