
Source | Baher Khairy, Unsplash
How do they do it?

Source | General Motors
Chroming, or technically chrome plating, is just a particular way of finishing a surface. The craftsman starts by cleaning the part's existing surface thoroughly, and then he "dips" the part in a chrome-plating vat that's filled with a chromium-based solution. Through a process known as
electroplating, electrical current is used to dissolve the chromium atoms and "plate" them onto the surface. The thickness of the plating is determined by how long the craftsman leaves the part in the vat. Once the desired thickness has been achieved, boom -- you've got your re-chromed surface.
Popular cars and parts for rechroming

Source |
Eisenmann Andrade/Flickr
Although chrome continues to be featured on some modern cars, it's more common among the older cars you tend to see at the shows. Chrome bumpers, for example, are pretty much dead and gone these days, unless you count a handful of pickup trucks. And good luck finding chrome headers under the hood; you're more likely to see a bunch of molded plastic engine covers. Candidates for re-chroming, include Mustangs, Corvettes, Chevelles, and certainly European luminaries like Ferraris and Lamborghinis, if your budget allows.
As far as specific car parts go, you've got the bumpers and headers but it doesn't stop there. Wheels are a big one, of course, and since they're so close to the road with all its dust and debris, they're gonna need more frequent attention than other parts. Chrome grilles, too, are in a vulnerable spot; you'll often see pitting and tarnishing up there.
But more broadly, just think about that C2 Corvette I mentioned, for example. There's chrome everywhere! You've got those iconic side-exit exhaust pipes, the fuel flap on the rear deck and various other exterior parts, not to mention all the chrome switches and knobs inside. Back in the day, chrome was a much more significant part of car styling. So if you want to make your classic car tip-top, you might have a real laundry list of parts that need to be rechromed.
Have you rechromed any of your car parts before? Tell us any tips you have in the comments.