To the original question - I found the following answer:
The first step in restoration is the complete removal of any surface finishing materials on the item. Grease and oil are removed in a parts washer that is serviced by a waste reclamation company. Paints & powder coating are removed by a hot tank stripper or by a dry blast method. Existing plating is removed by reverse plating in a 55 baume solution comprised of sulfuric acid, water, copper sulfate and glycerin. Rust is removed by blasting and or pickling in a hydrochloric acid. Whatever the requirement, Paul’s has available a suitable removal method that is designed to remove the previous coating without damage to the substrate itself.
Paul's Chrome Plating, Inc.
IIRC our downpipes are chromed stainless steel.
