A secret recipe!….only joking:
1) Frankford Armoury wet tumbler with steel pins and stainless steel 1mm ball bearings. 2 or 3 hours
2) large pinch of Lemishine and a splash of rinse aid. Add Luke warm water along with car wash and wax solution.
3) Thorough rinse, media separator and into the dehumidifier for hours. If rifle cases, I’ll spin them again to ensure no pins left.
4) If needed, I’ll lube with a mixture of lanolin/acetone…but this can dull the lustre.
5) Occasional wash of pins/ball bearings.
Factor in de-priming on most and it’s hard to justify the time, but when you see the cases gleaming like jewellery!