Correct. If the corrosion has started under the clear coat, then the best is to strip down and start over.
However, if your wheels are not clear-coated, then they can easily be cleaned with hydroflouric acid.
It is readily availible from most car-wash and detail shop chemical distributors. Its pretty nasty stuff, though, so you definately won't find it anywhere retail.
I'm not sure how wide-spread these two distributors are, but I have bought it from 'Castle' products and 'Wellworth' chemicals. They both sell the exact same product in thier own containers. A gallon is about $10.Worked awsome on the aluminum wheels for my Lincoln.
I got them out of a junkyard and they were solid black!
I tried buffing them with 'Mothers' and a Dremel tool, and got nothing!
A friend turned me on to this stuff, and you just spray it on, and hose it off! Wheels look brand new!!
It is unbelievable stuff! I got some pretty nasty skin burns using it though, so wear some gloves.
The stuff is a cute little shade of pink, so I figured it couldn't be too strong
...it was.