Go to Sears, get some white rouge in the abrasives department. Get some new buffs and fit them to a grinder and load them with the rouge. This you can use for the bulk of your polishing....the inside of the bends needs to be addressed, usually, with a 1/4" drill (they tend to run at higher speeds) and some felt buffs and load them with the white rouge. If you don't want to remove the pipes, just use the drill and felt buffs and work carefully around the pipes. There will be very fine lines from the buffing and it looks better if you pull them and do as much as you can with the bench buffer....and then you can finish up by hand with some liquid stainless polish. Always polish with the grain of the metal...in the case of tubing, that is around the diameter, not along the length.