In a plastic mayo jar (or whatever) mix 1 pint water, 1 cup white vinegar, 1 tablespoon salt and 1 teaspoon of laundry detergent. When all the solids are dissolved, fill the jar half full of cases. Screw on the cap and and shake for about 10 minutes or until the cases are visibly cleaned of fouling. After cleaning, pour the solution into another jar to be reused. Wash the cases under tap water to clean off any residue, then you can air dry them in the sun or you can place them on pie tins in a mild oven for a few minutes.
I usually drain the liquid and cases through an old strainer into a plastic bin, then I just pour the liquid back into the jar. Make sense.
Some cases might turn a slight pink color. That's just a reaction to the vinegar and nothing to worry about. You can make more of the liquid to be used a one time by just doubling the recipe. I have used large plastic containers to do more cases at one time.