Since I’ve had plenty of time at home, I’ve been able to get a few small projects done. One of which is cleaning up my original set of defroster duct hoses and heater Plenum. Just wanted to circle back to the thread to show you my results. I soaked the hoses in Evaporust for about an hour to remove any surface rust on the bands, then I used a toothbrush to scrub the bands gently, then rinsed and wiped down the defroster ducts. I then gave them a light coat of Scotchguard spray. This worked well and they look almost new.
For the heater Plenum I used a soft damp paper towel with some foaming window cleaner so as not to damage or get the cardboard soaked. Next step is to clean and repaint the bracket and control arm for the flapper.