Back years ago when I was in gradeschool, my 4th grade teacher would give us a quarter for every fly we killed in the classroom.
He didn't care how we did it, but he had to see the dead carcass before paying the bounty.
We got rather creative, and my favorite was a rubber band pulled back on your pointer finger and released.
I still enjoy killing flies and bees and stuff like that to this day and over the years, I've gotten rather good at it. I didn't even own a fly flapper until I got married. And admittedly, she was the one who bought that.