I always clean primer pockets to assure proper seating of new primers (Dremel tool with wire brush). I seldom worry about cleaning my own brass, but I do clean range brass or other fired brass that finds its way to me.

Hot water and dish soap in a plastic bucket is a good first step, 4 or 5 hours soaking followed by two rinses to carry off the soap and other residue. Spread them out on newspaper in a sunny area for a few hours and they are cleaned and dry, ready to process.

I have a vibratory tumbler with walnut shell media, but I seldom use it. Last time I recall loading it up was a batch of .30 Carbine brass with some pretty heavy surface oxidation and tarnish. After 8 hours in crushed walnut shells it all looked like new, but did require routine decapping and primer pocket cleaning to remove excess media.

Basically, I stopped worrying about reloads with cases that weren't looking factory-fresh and shiny along about the time Jimmy Carter was doing his best to destroy the American economy. I don't really care if my reloads show a bit of tarnish or a lack of shine, as long as they function properly I'm a happy guy.