Origin In April 2021, many internet users encountered a seemingly clever trick to deter wasps and yellow jackets from entering their mailboxes: Simply place a few dryer sheets inside. This piece of advice came from a post on the “You Should Know” section of Reddit from someone who identified themselves as a letter carrier. The post informed readers that if they found a dryer sheet in their mailbox it was likely from their mail carrier who was attempting to thwart “those dastardly devils” that had built a nest in the mailbox. Letter Carrier here. We’re almost to the month of May which means nice weather, hanging out outside, school closing for the summer, and the return of those dastardly devils: Yellowjackets and Wasps.