I read an article recently where a guy puts his cartridges in a bottle of water as soon as he shoots them. Starts the cleaning right away.
NRA used to (still does?) recommend this solution:
1 - QT Hot Water
1 - Cup Vinegar (can use citric acid)
1 - tbsp salt
1 - tbsp dish soap
Soak for no more than 15 minutes.
1 Qt water
1 teaspoon baking soda
Soak for 15 minutes.
What I've started doing is take the above solution, leave out the vinegar so it's just 1 - QT Hot Water, 1 - tbsp salt, 1 - tbsp dish soap, throw the brass in there at the range. You can leave it for several days in that solution. Then when I'm ready to actually wash it, pour in the 1 Cup Vinegar, agitate, let sit for 5 minutes, agitate, sit 5, agitate, sit 5 pour and rinse. Then do the neutralize. You'll want to rinse after the neutralizing about 4-6 times. I put the brass back in a screw top container and shake it real well.
It comes out looking nice.
I do tumble in a vibratory with lizard litter (walnut shell) and Nu-Finish. Brass looks brand new, better than a lot of factory rounds.