This works with flake powder. I KNOW!!!
If the shot is new (not reclaimed) get two plastic cups 8-32 ounces.
Put some of your mixture in one cup.
Slowly pour that mixture into the other cup.
The round shot will easily roll out leaving the powder.,
Some powder will adhere to the shot.
The first cup should be shot free.
Put it aside
Repeat as needed.
Reclaim shot requires many repetitions, again, I KNOW.