my brass always looks dim, and rough / old looking ... It's not, but that doesn't stop me thinking it .. Lol
If you are already tumbling with e.g. walnut shell you should easily be able to get the outside of the cases looking better than new. E.g. as others suggest with added brasso, or I use a teaspoon of jewellers rouge, which is I think what the commercial preparations use (the ones that are red/brown in colour).
One teaspoon lasts the life of the media, thousands of cases, is odourless and no potential for the ammonia to damage the brass.
If you over-do it there can be a trace of red dust left, which wipes off.
Some also add a splash of liquid carnauba car wax for extra shine, and possibly tarnish prevention.
I deprime before tumbling and the stuff I use (walnut shell reptile bedding) gets most of the gunge out of the primer pocket, certainly well enough to need no extra cleaning.
Primer pockets don't need to be surgically clean, as long as they are clean enough for the primer to seat properly thats good enough. Flash holes need no special care, the depriming pin ensures they are clear.
I think the SS tumbling method is definitely the best, but I can't justify the expense.