FA makes a media separator that's enclosed. Top and bottom section. The top section has a screen to let water out. After wet tumbling I pour everything (including dirty water) into the media basket in the bottom section and put the top on. Rotating the media separator while it's still sitting in the dirty water helps get all the pins out of the cases. They fall to the bottom while the cases remain in the basket. Having the top section on helps keep the pins from flying everywhere (they're like Mexican jumping beans when rotating the separator).
With most of the pins in the bottom section I tilt the entire unit to start draining out the water. There's a small screen at the corner to help with this.
Next I take the top off, put it in the sink, and dump all the shells in and rinse with cold water. That's where the screen comes in handy because it lets all the soap and dirty water out. The screen also catches the remaining pins (the majority are still in the bottom section). Then I lay the cases out on a cookie sheet and cook for about 45 minutes at 170 degrees. If they turn orange I put them in a bucket with a little lemi-shine, they turn yellow, then I cook them again.
While they're cooking I use the magnet to spread all the pins out on a towel to dry. Overall it's a neat little unit.
Last night I cleaned 1,500 .45 ACP cases at once. It brought the tumbler right to 30 lbs.
For my second load I mixed in the remaining 300 .45 ACP with 9mm, .40 S&W, 38 Special, and .223 cases. Big mistake. They turn themselves into Russian nesting dolls. Not only do they stack inside each other trapping pins, but those pins often wedge the cases together really tight, especially .40 cases inside .45 ACP cases. What a PIA.
Here's the media separator I use. I definitely helps contains the pins after tumbling:
LINK