Interesting that most people haven't had good luck with white vinegar, I've had great success with it on small chrome pieces. Soak them for a few hours and wipe the rust off with a paper towel. For larger pieces like fenders or wheels I use 0000 steel wool with WD-40 and then clean it with a good degreaser and then polish them. I can already hear the "NO don't use steel wool, you'll scratch the chrome" choir but I have seen no evidence of scratching from the 0000 steel wool and anything old enough to require rust removal has plenty of fine scratches to begin with. I've used it on paint with heavy surface rust as well.

Here's a '55 Columbia I did the 0000 steel wool/WD-40m treatment on, left side as found, right side after a few minutes of rubbing, it would have gone faster had I removed the barn dirt and pigeon droppings first but it was about 20 Deg. F when I did it.