We got one of those electric fly swatters, but the thing is too heavy to swing fast enough to pop flies like you'd want. So on a hunch, I checked YouTube for a trick to make them more effective.
Basically take a styrofoam plate with a little food on it and tape it to the fly swatter, and zip tie the switch down and set it wherever the flies are at their worst. For bait, I just put a smear of ketchup and ranch dressing on a paper towel.
https://youtube.com/watch?v=tDZb2l2A888
We managed to kill over 30 flies in about 2 days. Heads up though, they're not designed to be left continuously powered on, the batteries will end up dead and leaking after a couple days.
I had to toss the batteries and open up the swatter handle to clean out the battery juice off of the terminals so it won't rot out.
But hey, aside from the inconvenience with the batteries, the trick just freaking works ๐