So today on my walk home I came across a rear wheel. A 27" Mavic Module 4 rim laced to a campy rear hub. It was in a box of "take me" junk. Yes! The weird thing was that I wanted to build a coaster wheel for a townie and have been considering finding an old mavic rim to match the front rim on my bike (so weirdly coincidental).

Anyhow, two questions.

The nipples on the rims are rusty. I was considering cleaning off the rust and then painting the nipples to prevent them from rusting again. Is there any other solution?

Secondly, how do I identify the type of campy hub? It a low flange 36h freewheel (not cassette) hub. It's got the campy logo on the spindle but no other marking. It doesn't have a spring clip or grease hole on the axle. Also along the side of the threads, there are marking that note that it's BSC, 24tpi, English. What else can I look for to figure out what type of campy hub it is.

Thanks.

"I was considering cleaning off the rust and then painting the nipples to prevent them from rusting again. Is there any other solution?"
Perfect opportunity to try oxalic acid solution in a container that will allow you to partly submerge the rim and rotate it all 360º until done. Paint with whatever paint you like, once the rust is gone and the ferrules/eyelets are dry...I've never gone to that much trouble to abate or prevent ferrule rust...if it isn't bad and I'm just relacing an old rim I use an electric eraser (remember those?) with a coarse gritty eraser strip...that makes it very quick.