Only a 3 year old powdercoat. They are fine. The Transluscent Blue didn't cover up the "fatima" on the valve covers. Paul even cleaned them up with a wire wheel before coating.
I just use simple green, diluted to a 1:10 solution on the hard areas. Then I will go behind it with a water damped cloth to clean up any residue. Some spots i just use a damp cloth.
Then I will go behind it with cleaner wax, Aerospace 303, etc.