Paint the tops with Rustoleum, dip the threads in Milk of Magnesia. Depending where they're used you could just buy stainless steel fasteners.
Some form of plating is preferred to paint on bolts, since a plating or phosphate coating will resist chipping more readily than paint...If you have to paint, try and get some socket liners that prevent chipping the paint during install.
I soak them in a jar of vinegar to remove rust (some times wire wheel) and coat them with Rustoleum flat black.
Last time I got some stuff zinc-chromated (that pale gold look) was over 30 years ago and over $100 then for a handful of small pieces that would fit in a small USPS flatrate box. My bud uses Dupont epoxy primer for durability, then tops it with Rustoleum for color.
I've had painted bolts hold up for more than 10 years with only slight losses in gloss from time/heat. Paint holds up just fine if you are sure to clean/prep them well enough before coating. Proper curing before assembly is also critical to avoiding heavy chipping when reinstalling. Even if you do get a boo boo at assembly.. touching up with a modeling brush will keep it from further chipping/corroding.
some of this stuff and a set of those socket liners are on my list things to get... thanks Guys...:Handshake