Removing brushed on RUST-OLEUM from axle housing?

i tried the wire brush and it was too slow to remove the paint, so I broke out a flapper wheel and the paint flew off/ And its giving the metal a nicer finish thhen the factory had.

I got a 6" wire wheel and put it on my 4" grinder to remove road tar and crap from front suspension parts and it flat tears it up.
It's a bit like hold a pissed off badger by the tail, but it sure works if you don't want to remove metal. (next time):D
I like the flap discs too, and removing a bit of metal on what you are doing just makes the surface look better.