Use a good chrome polish and then wax it with a good paste car wax. You will have to do it again probably every few months, once rust starts it is hard to get it all. Another thing you could try is clearcoat on it after you remove as much rust as possible. You could also try steel wool, like Brillo pads with the chrome polish.
Rick Kilpatrick, AAS Automotive Systems Tech, Alamance Community College, Class of 99. 06 5 speed manual Mustang with Pony pkg : GT Mac Mufflers, true duals with one custom pipe. 2.5" system. GT bumper cover, all installed March 7&8 2006. AFE Stage 1 CAI, Motoblue Underdrive pulley, GT aluminum shifter knob, honeycomb rear blackout panel,and dash kit installed. Roush hood scoop and side window louvers installed. SS taillight trim has been installed, new alum. GT steering wheel installed.