Excessive effort. Just tumble them in walnut if you REALLY need to clean them. I typically wipe my precision rifle cases and lightly scrub the neck only with a mild Scotch Brite pad by hand. I then hit the inside of the neck with an old 30 cal bronze brush. Anneal, size, clean primer pockets (probably unnecessary as well), load.
If they get really dirty (wet shooting day, etc), I will tumble them in a dry crushed walnut mix.
RMD