On the Stainless Steel Media tumbling...
Here's a good How-To video, Stainless Tumbling
I do it a little different. I picked up a fine gauge flour sifter from Amazon that I run water through while picking out my Brass. Much less chance of losing some pins down the drain. Though I'm also playing around in my head of an idea involving a magnet, and a ziplock baggie cover. Stick the magnet in the baggie, pick up the pins, turn the baggie inside out to pull the pins off the magnet.
The main thing to watch out for, as a corrolary to those flash hole walnut bits, is a stainless pin staying inside the case. That's why we rinse them upside down underwater, to flush the pin out.