Yeah, don't do it. It won't stick anyway to a previously oiled blade unless you degrease it, and I must say that in contrast to gloppy silver and gold paint, blades that have been lacquered (one does encounter it fairly frequently, with yellowed or red-faded old lacquer; it seems to have been popular with English and Euro-North Americans in the early and mid 20th) are usually fairly easy to clean off (but modern spray acryllic might well be more difficult), and it does seem to have a certain preservative power (so do the ugly metallic paints, but they can be SOOOO hard to get off!
). If the laquer seperates from the metal, as it sometimes does, then the pocket underneath becomes like a little moisture chamber, though. I think you're better to stick with waxes and oils; cosmoline seems real good for longterm storage (is that commercially available? Is it truly as same as drugstore petroleum jelly as it seems?).........I like a plated blade (though others don't), but that's not a realistic after-market protection for an assembled sword or anything......too long winded; oil and/or wax. Microcrystaline wax, like "Rennaissance Wax" or some fancy car waxes, is usually recommended, as the danger is not just from large packets of water that will bead up on ordinary wax, but from water vapor in the air, acting at a smaller level of reality. Alternately, good gun oils with Teflon or graphite that claim to leave behind a microscopic protective layer usually work fairly well, too, although they rub off easily and must be reapplied. I've heard of using bicycle lubricant, too, but know nothing specific there.