Brian
If your #1 is one of the "oldies" the line guard is made of nickle silver,it just gains a nice patina.The corrosion is probably on the frame itself,right where the screws are threaded into the frame ,no? If THAT'S the case,it's caused by electrolytic action between the disimilar metals. I'd just gently clean out the "powdered aluminium,use some Locktite,and continue using a very fine reel !!. There are two places on the West coast that CAN fill in the frame,re bore and thread the holes,repaint and restore the reel to perfection.
Cheers
Brian