I have tried a bunch of products and most didn't work that well and some left it dull. I did use fine grit paper (600/1000/2000) to get out some of the scratches in some places.
The best product that I used last year is Blue Magic Metal Polish Cream. It will remove the tarnish from the metal as well as polish the surface for a better shine. What I do like is that it will leave just a touch of patina behind so that it does not shine like some over restored piece on the car but you'll have to look closely to see it. I used paper towel because the paper acts as a mild sandpaper helping to get the metal to polish up. I did it all by hand with some CCR and Stevie Ray Vaughn playing.
