An acid-based wheel cleaner is good to clean up a sooty tip, provided you wash it straight off afterwards. A metal polishing paste, like the one from Meguiars, will bring the shine back easily. If you can take the exahust off the car, taing it to a polishing wheel will work wonders. I'd be loath to use a small polisher, like a Dremel, in an area like this.
UE? EUA? Jeez, just worked that out. Is Europe now a country?