Cosmetic, sand and paint. When the paints off, you can get a good idea of the penetration. I don't know much about lugs tho- I've only sanded rust outta butt-welded chromo.
Nice yummy red cranks n' stuff. I love red components.

An idea is..( I did this to a couple frames now) strip with gelled stripper, sand with wet emery paper, buff with steel wool and clearcoat. lugs look real nice clearcoated. Easy to maintain.

To bad it doesn't have the internal cable routes. I'd be more interested in looking INSIDE the headset, seattube for rust.