After rust freckles have achieved a foothold, nothing will remove them completely, short of a re-finish. Light oil (or bore cleaner) and copper wool pads like "Chore Boy" (many supermarkets carry it) will do about all that can be done without further damaging the original finish and will make the area look better. If you are not an absolute purist, dabbing a little cold blue in the area (I like Brownell's Oxypho Blue) after the oil/copper wool treatment and following de-greasing might help hide the damage a little more. But it won't go away.