A friend has the most efficient BP case clean-up Ive seen to date. He does the 'jug trick' mentioned above. The ride home jostles it even more. Once home he dumps them in an old colander and runs clear water over them for a few minutes (shake them up a couple times) and lets them drain a bit, shake & drain again, then they go into the food dehydrater trays to run a couple hours & cook off the water. An oven at 150 would do the same. He finishes with the tumbler overnight and they are slick & purdy, ready to go.
BTW, He uses straight BP loads, and quite a bunch at that, and hates clean-up too, so this really works well.