Surface rust is sort of for lack of a better description like a water well. Underneath you have the rust with a hole thats bleeding to the surface. If you apply a rust kill type of product it will take it off the surface but it will also penetrate through the hole into the rust below. When you rinse the solution off you will be unable to get what remains below the surface out and it will errode the integrity of the finish. The easiest and safest way for the finish if you do not want to refinish, is to use a very mild polishing compound to remove the surface rust. Follow it up with a couple of coats of clear coat wax. Keep the frame out of moist conditions and keep it waxed and it will hold it for quite a while. Putting more clear coat on won't accomlish much unless you remove the rust beneath the paint and thats refinishing all. Mother's Chrome Polish will remove the surface rust on chrome without damaging the chrome. Apply some wax and thats it other than replating because the cause is again a microscopic hole through the chrome to the metal below.
Good Luck,
Dennis Smith
Body Shop owner for 40 years
Waco, Texas
USA