My grandfather had a large gunroom years ago, filled top to bottom with the most marvelous collection of old Remingtons. Not only did his gunroom smell like Hoppe's, but much of the house reeked of it as a result. It's a smell you either love or ... would rather have cling to the garage or the workshop or the outhouse. But there's no mistaking the odor. Robert Duvall might say that it smells like ... victory.
I've used Hoppe's #9 for forty years on both blued and stainless guns...no problemo. HOWEVER, nickel guns are a different matter. Hoppe's will screw up a nickle finish if left on. Something about the mix of metals in nickel causes Hoppe's to eat away at it. Perhaps the copper content? Anyway, on blue and stainless it works great. And if you sneak in your wife's room and steal one of her perfume sprayers, you can use #9 as a cologne