Cleaning brass whats that Fred ?
But seriously when I do get the inclination to handle nice shiny brass, which is very seldom I might add, I throw them in the ultra sonic cleaner. This cleans the inside neck wall and primer pockets, the brass comes out clean but not real shiny. If you want to go to the next step and really impress the blokes at the range you need to throw them into the tumbler with a bit of Brasso and crushed walnut media, (Now I have read that the ammonia in the brasso is not a good idea, but I know blokes who have done it for ages with no ill effect) There are probably other compounds you can get that do as good a job but I have never bothered to research any of them.
Then you take them to the range pull the trigger and they come out dirty and you wonder why in heck you spent all that time cleaning them.
This is the sonic cleaner I purchased, got the 3.2 litre one.
https://tinyurl.com/y2y5p6xu