Keeping away buffalo knats!

I know buffalo knats have been a problem in a lot of areas lately. We have experienced them in the past camping. My father-in-law put to use the idea of using vanilla exteract. He is a carpenter and was working outside with another buddy last week. He had also heard that vanilla extract would keep them away. He decided to try it. His buddy declined and said he didn't want to smell like cookies. Well my father in law left without getting bit once. His buddy however walked away with several welts after getting bit. So there you go......vanilla extract does work!