Hang out a plastic transparant bag in the sun with 75% water filled in it. Flys seem to get dizzy flying to it and turn around ( that's an explanation I came u

Hang out a plastic transparant bag in the sun with 75% water filled in it. Flys seem to get dizzy flying to it and turn around ( that's an explanation I came up with why it works, don't know if it's the explanation) If it's a outdoor tent, that means 4 hanging bags.