I don't remember seeing that thread.
But I have stipped wheels before.
I used Aircraft Remover to get the clear off.
I think I read that the aluminum underneath is pretty smooth, but it can't be all that smooth or else the clear won't stick to it.
I imagine then you would polish the metal and go through the grits up to 1500 or 2000.
I polished lots of aluminum parts before--very time consuming! (At least my parts were.)