last bunch of brass I put a little bit of TSP with the brass in a strainer in a bowl that fits the strainer, poured in boiling water, shook it around for a while dumped that water, rinsed off the casings int he sink with hot water, then a final rinse with the second half of the kettle. Took a couple minutes, drying took a bit but they were cleaner than when I started.
I'll break down and get a tumbler one of these days.