I have a cz 452. Thankfully I haven't dealt with rust on it that I can remember but sometimes my rifles and occasionally a handgun will have a small amount of surface rust - especially before I found a thicker oil I liked.
Your options depend on if the rust is on white steel (not blued)/stainless or blued steel. The basic strategy is pretty simple: mechanically knock off the rust with minimal damage to the steel and protect with oil afterwards. With blued guns, the bluing only goes so deep and often the finish is glossy so you do not want to leave scratch marks.
Some start with steel wool but I don't like to for 2 reasons: steel can scratch steel, and as it breaks off it can rust in the future if it's not cleaned thoroughly.
I use a brass brush, even the round ones from a cleaning brush and have at it. I've also used a penny if I need to apply more pressure. Then wipe it off with a clean rag and the yellowed color should come off. If not, use a gun cleaning solvent to help remove the yellow. If this is just surface rust chances are any bluing underneath is okay. Then coat with a "good" oil. What's a "good" oil? There's lots, but the generalization I can make is that for rust protection (rather than lubrication) you want something thicker that will stay put. This can be a heavier oil or a grease. Even so, people typically wipe off all the excess until a thin film remains or else it will attract dust and potentially trap moisture with the dust. After all the products I've tried, currently I use Eezox. (google Eezox and corrosion test). However I'm considering switching over to Ballistol as I never minded the smell and I never wear gloves when cleaning so perhaps the non-toxicity might do me some good.
If it's stainless or white steel, there's a nice thing I've found called the Birchwood Casey Rust Removal cloth. It removes rust / fouling chemically and mechanically I believe. Boy is it fast. I think it has aluminum oxide particles as an abrasive to polish the surface at the same time. So if the surface you're looking at is a matte stainless finish, it may become shiny or slicker with repeated use but if that doesn't bother you, this thing works FAST. On a CZ452 bolt I wouldn't hesitate to use it.