Here is a couple of solutions that are from the 6mmBR.com article. Check out the full article and see the pictures of his results.
http://www.6mmbr.com/ultrasonic.html
ULTRASONIC CLEANING — Baney's Best Recipes
My ultimate solution resulted in shiny brass that was 100% devoid of carbon, inside and out. Even the carbon deposits on the neck and the primer pockets were completely removed! My objective had been accomplished! Dirty old black brass came out like new inside and out…I was amazed. Not only did my protocol work well, but it was the least expensive option in the whole test! For "Cheap and Clean," this is the procedure I settled on:
CHEAP and CLEAN
24 minutes - 50% Vinegar + 1 Drop Dish Soap per 8 ounces water
480 seconds - Baking Soda (BS) in water (1 grain BS per ounce of water)
480 seconds - Hot Water
480 seconds - Distilled Water
Total: 48 minutes
Cost: Less than $2.00 per gallon
And for a Super Shiny and FASTER End Result, Add BC Solution
Since the BC solution had worked so well to shine up the cases earlier, I attempted to work it in with the vinegar procedure to streamline it even more and give even better looking brass. So for a couple dollars more, you can have 100% clean cases, which are even shinier than the "Cheap and Clean" procedure above. So this procedure I'll call "Clean and Shiny."
CLEAN and SHINY
24 minutes - 50% Vinegar + 1 Drop Dish Soap per 8 ounces water
380 seconds - Birchwood Casey (BC) Case Cleaner
380 seconds - Hot Water
380 seconds - Distilled Water
Total: 43 minutes
Cost: $2.00 per gallon for the Vinegar and $4.00 per gallon for BC Cleaner.
This "Clean and Shiny" procedure gave me the best combination of carbon removal, case luster, speed, and economy. The "Clean and Shiny" regimen also eliminates the neutralization step, as the BC cleaner acts as a neutralizer. Even though it contains a few acids, they must rinse off more readily than vinegar. Regular household vinegar is 5% acetic acid (2.5% when diluted) and the BC cleaner contains 3 different acids, one of which is phosphoric (the same found in pepsi). It starts at over 50% acid as a concentrate, and a little over 3% when diluted.
Case Care Following Ultrasonic Cleaning
After removing the cases from the final distilled water rinse, I simply blow them out with compressed air and lay them on a paper towel to dry overnight. A hair dryer works well too, especially if you get the air in the case mouth. In the morning you have clean, shiny dry brass ready to size. If you have no air compressor, simply whip them around by hand a few times to force any water drops out of the case mouth. Then lay them on a paper towel to dry overnight.