I bookmarked this back when posted and promptly forgot about it. It was one of those "I'll get to that someday" things. I was depriming some brass last night and dropped quite a few to the floor. I remembered this, looked it up today, and put the piece of plastic in place.
I just went out and deprimed 300 pieces and didn't lose a single one.
Great tip.
Nice! Glad it works for you!