I've messed around with various recipes with citric acid from a wine supply shop, dishwashing liquid, etc. Settled on hot water and about a tablespoon of the citric acid in a sturdy 1/2 gallon Snapple bottle. Only 5 minutes, then rinse again with hot water. I save the solution and use it cold for several batches.
These are all deprimed with a Lee universal decapping die. After rinsing I throw them in a dedicated towel and roll them around, then onto an old cookie sheet to dry in the sun. If I want more shine, 20-30 minutes in the vibratory case tumbler makes them look factory new.
Cases size better out of the corncob 'n polish media, too.
There is a huge thread on cleaning with citric acid on the cast boolits forum.