Oxalic Acid bath is the only thing that will remove SURFACE rust, and get a new shine at the same time. But you mention bubbling and black, so i am guessing that the rust has gone down to the steel under the chrome in which case its fooked and nothing but a strip down and re chrome will do the job. If you use the coke method all you will end up doing is bursting the bubbles and more flaky chrome will begin to show.
Have a nice day.