Using a good metal polish and microfiber cloths you can bring a S&W to a much brighter shine that looks pretty good.
However, it'll never be a true mirror polish, because metal polish can't remove actual machine marks.
In order to get a true mirror shine requires metal polishing equipment.
Here's a specialist that does true mirror polishing.........
America's elite, veteran-owned firearm polishing service. If it must be perfect, it must be Patriot.
www.patriotgunpolishing.com