After shining lots of "brightwork" in the Navy many years ago, I've found NEVR-DULL to be perfect for my exhaust tips. I wear disposable nitrile gloves when using it so I don't end up with black polishing residue on my hands/fingers.
Collinite No. 850. It's a very fine grit metal polish and wax all in one. Very inexpensive, goes on then right off before it dries, and leaves a wax on the metal that allows a quick wipe with a cloth for months later to remove 99% of any exhaust residue. My polished APR tips look brand new with no scratches using this for years.