I tumble for an hour or so, resize, trim, ream & chamfer, clean primer pockets, wipe off with acetone, and then tumble for a good 10 or 12 hrs.. I started using acetone or denatured alcohol many years ago, primarily to eliminate all lube residue.
It is very important the outside of the brass and chamber be free of any residue, especially anything that is a lubricant or moisture. All firearms rely on case seize to facilitate the complete directional management of the high pressure gases created by the burning propelants. Without complete management of the pressure seal between those two entities, bad and unpredictable things begin to happen including ruptured cases, lug set back, and a host of other undesireable things. I don't usually handle my loaded rounds with my bare hands if I can help it.