Getting off rust on brake disc Options

[whatthe]

Im not sure if this is in the right section. But since ive got my rims i want to get rid of the rust that i can now see on my brake discs. Wanted to make sure on how to do it. Is it as simple as taking some sandpaper and rubbing it until it comes off? If so how do i polish it back up too?

-What

[whatthe]

I cant really find a picture but the part i want to sandpaper the rust off the where the studs come out of the circular barrel object (if that makes any sense) and also the rotor edge along the tip at the end. If i dont make any sense ill take some pictures in the morning about the areas i want the get rid of the rust