Re: First rust found-suggested fix
If you only have access to rattle cans, I strongly suggest using appliance epoxy. In rattle cans it is not a true epoxy amide but an epoxy ester which is still infinitely better than the usual alkyd enamels you find in most rattles.
Be sure area is sanded to BRIGHT metal before painting. Apply multiple coats-the more the better. Weather dependent, It will take up to a week to fully cure but should be handle able in a few hours.
If you do not like the shade of black, wait until it is fully cured, lightly sand and top coat with your favorite black enamel
You can find it at any Big Orange Box or Big Gray Box