Also, they’re sensitive to moving shadows. As with motion sensors, if you move slowly enough, they cannot sense you. Slowly circle behind them and they jump into your death mitts.
Anyway, this has worked out better for me than a Bic lighter and hair spray. But that works too.
Move slow enough too and a fly won’t percieve you moving very well. Benn Jordan’s video about what the world sounds like to different animals taught me that. Flies basically live in constant bullet time.
11 minutes in for the insect segment: https://youtu.be/Gvg242U2YfQ