Please help...

This old Vulcan metal finish has become worn, patchy, mottled with some light rust. It is not worth a professional refinish, nor bluing kits, I was thinking a rattle can jobbie. Obviously good preparation, etch primer a black top coat. I have used rattle cans on many items, but, yet to find one that is fairly robust and scratch resistant. Why is it that any drip of paint falls to the ground, rattle can or not, is difficult to remove when dry? They seem to like a dusty surface!

Any advice on which can to buy will be most appreciated, thanking you in advance.