I use a vibratory cleaner, walnut shells, NuFinish AND a few used 'dryer sheets' (clothes softeners). My wife thinks the dryer is eating them. I'm good with that.I can run my Dillon vibratory cleaner for about 2 to 2 1/2 hrs using walnut hulls and car polish and the outside of the brass looks great. It doesn't clean the inside, but in 40+ years of reloading, that's never been a problem.
The dryer sheets collect a lot of the dirt/grime that is removed by the walnut shells. If you don't 'clean' your media this way then you will always have less than shiny brass.
The NuFinish does help impart a protective 'finish' on the brass and probably helps a little in removing tarnish, but the abrasive action of the Walnut Shells is responsible for most of the work.
The Dryer sheets come out looking pretty dirty after a couple of uses, proof that they are helping remove the crud that is floating around in the media.