If it is purely aesthetics you are worried about somebody should have ideas on removal. If you are worried about structure or safety this surface rust is normal on all cars.
I painted mine with the calipers and now they don't rust and have a nice look to them. All I did was take some rustoleum, sand it down, then paint it with high temp paint from DupliColor. Works great and has been on there for over a year.I am discovering the downside of having open wheels! Yep...RUST which appears to be forming all around the rotor hubs. It is most noticable in the rear! I really don't feel like taking the wheels off and sanding and painting the hubs. I am wondering if anyone has tried a rust dissolver or something similar. Can anyone suggest something?