Hi Gregg It depends on what the handles and key plates are made of. If brass, a heat gun and a brass scrub brush (looks like a big tooth brush) should be able to get off all the old paint. Then you can polish using a course rubbing compound then a fine rubbing compound with a cotton cloth.
If cast iron, this will be a bit harder, as iron often has small pits that paint just loves to hide in. The heat gun and brush may work ok, but you'll probably have to use a chemical paint stripper also.