That's an old trick that I was taught by the porters to clean up
rusty bumpers on the used car trade-in's when I first started
working at Phil O'Keefe Chevrolet back in the late 50's.
Here are a couple of original chrome plated hub caps for a '50,
3600 that were badly pitted and rust stained when I got the
truck back in '05. The reproduction hubcaps won't clear the
free floating hubs on the rear so I had to use the original
ones. These four pictures was taken just this morning. I hadn't
cleaned them for quite a while, years in fact, and you can see
the pits are quite pronounced. A quick rub with a wade of foil
and from a couple of feet away the rust pits almost disappear,
They will look even better after a wax is applied:
http://www.pbase.com/dennygraham/image/154683852Click 'next' in the upper right corner to see each one.
I think what happens is the aluminum is much softer than the
chrome so it won't scratch it but it is abrasive to the stains.
I also think it leaves a little of the aluminum in the pits
that helps to hide them.
