One bad-ass product (penetrol) A more refined product of BLO (boiled linseed oil) witch is the base product of oil based paint. Penetrol is very effective by it's self dries amber and kills/stops rust by denying it water and CO2.
Will not harm paint will soften /deform some rubbers
Google out-door metal art/sculpture to read testimonials of how good it works on raw metal.
I'm currently doing my rims and spokes/nuts penetol penetrates like crazy and dries into a first class finish.I have been known to spray/undercoat cars/trucks with a pump up sprayer like ones for spraying wood decks... with the cheaper BLO
incredibly effective products with minimal prep.