I deprime after tumbling and don’t worry about cleaning the primer pockets.
I actually broke a decapping pin trying that. The corncob kernel was stuck on the inside of the flash hole and just deflected the pin to the side where it broke trying to punch a hole through the case web.
Ultrasonics can be made to work. The following was done in a 35W/gallon (typical) energy density cleaner using the Frankford arsenal 5% citric acid solution, 140°F temperature. But I was using glass beakers in the big 2.5 gallon unit to separate cases at different stages of clean and rinse, and subsequently, it was pointed out to me that glass containers in an ultrasonic can absorb a significant amount of the sonic energy. It took 45 minutes.
You'll notice the pink that Marchbloom mentioned wherever the original case had significant oxidation, but it is very thin and fifteen minutes in the green Lyman corncob removes it and leaves the brass shiny. This is assuming, of course, that you want to polish. If you don't, the case tends to darken its yellow a little and that kind of oxidation actually protects the brass, as citric acid treatment is used on brass that is to be stored for long periods.
To show how the citric acid leaves a pink stain in place of oxide, here's a .45 Auto case I found pressed into the mud at a range just after a rain that had probably been there a year or longer.
Running detergent together with citric acid (usually as Lemishine) can be counterproductive. The acid has a pH below 7 while a lot of detergents have a pH either above 7 or at about 7 with buffers to keep it that way. These weaken the effectiveness of the acid. Besides, citric acid chelates minerals in the water, so it is a strong water softener and makes the water plenty slippery and able to clean. That is why no detergent is in the Hornady formulation. I used to add detergent to suspend dirt, but stopped.
I should go back and rerun the experiment with tarnished brass and the big ultrasonic without the glass beakers. But at the last NRA Annual meeting, I ordered a 1.5 gallon unit with 100W/gallon energy density. The wave action on the surface is much greater than with the other unit. The difference in cleaning power is like night and day, so I probably won't get back to the other one. Besides, I don't have any more of the heavily oxidized cases on hand. Those came from a flooded basement in the family, where they got wet and weren't discovered for two or three years. They all polished up just fine and shoot just fine.