For this purpose, I imagine DuPont Multi-use Dry Wax lubricant (Google it) would be effective. It's wax dissolved in a carrier, so you could simply coat the nipples and spray wherever you need it to work into. It lasts a long time, waterproof, prevents corrosion, and doesn't pick up dirt. It's my bicycle lubricant of choice; I only use grease for bearings now. My stem bolt gets coated in the stuff, the inside of my steel frame is coated in the stuff, seatpost, threads, CHAIN. I even spray some on a rag and wipe my frame down to clean it (the carrier solvent cleans well and leaves a thin wax sheen behind).