Just saw a post on a chevytalk.com showing CLR used on a very rusty old car and was amazed! The difference was unbelievable. Take a look and please comment.
Look under 1958-1960 Impala and then "CLR on paint subject".
"Do not use CLR on wood, clothing, wallpaper, carpeting, marble, terrazzo, natural stone, colored grout, painted or metallic glazed surfaces, plastic laminates, Formica or aluminum."
It appears to use CLR on the painted finish of your car is at your own risk.
CLR on brass is questionable at best. Scotch brite will remove the corrosion b y itself. Follow with something to keep out oxygen, and the cleaning will last for years.