It may appear to "remove" some oxidation, but only the very top portion which has become completely detached from the actual paint surface.
See "oxidation" in dictionary, the breaking apart of the molecular bond, etc, etc.
A clay is not agressive enough to do so.
You may wipe an "oil" type product on the surface to create an optical illusion of removing oxidations, but once the oils evaporate, the condition is still evident. (I.E, think of women's make-up)
There are two ways to remove oxidation short of sanding and repainting.
One is to "chemically" remove the majority and then do a light polishing with a rotary buffer, correct pad, product.
or
Two, use an agressive compound, cutting pad and abrade it from the surface, followed by polishing with a correct polishing pad and polishing product.
Ketch