Have you ever opened up your mailbox to retrieve your mail and found what looks like a dryer sheet inside? This has become quite the phenomenon of late, as it has been happening to many people all across the country.

But if you’re one of the people who has discovered this, there’s no need for you to be confused or suspicious.

There’s actually a totally innocent explanation for why this has been happening.

Why Dryer Sheets?

Every job has its occupational hazards, but postal workers have to deal with a particular danger that would probably surprise those who have not worked in the field: bees and wasps.

Bees and wasps tend to make their nests in dark and enclosed spaces. That’s exactly what a closed mailbox is.

When a postal worker opens up your mailbox to drop off your mail, they generally have to put their entire hands — and even much of their arms — into the box. If a bee or a wasp happens to be nesting there, it will be disturbed and it will strike.

One mail carrier actually took to Reddit not long ago to helpfully explain the dryer sheet mystery to others. He said, “I can’t tell you how many times, especially during this part of the year, where I’ve opened up a box to see a little nest with three to five yellow jackets just chillin’.”

As the postal worker explains, “We’ve found that they hate scented dryer sheets. If we encounter a box that is a problem…we’ll often put one in there, and it does the trick.”

As it turns out, then, dryer sheets not only keep postal workers from having their hands needlessly stung by wasps or bees, but they also drive those creatures away from your mailbox if they are found there.

Commenters on this Reddit thread then took to informing people about other unexpected uses for dryer sheets. Restaurants use them on outdoor clothes for the same reason that postal workers do. Some claim that they can even help potted plants to grow better because they ward off bugs.

Of course, if your mailbox already has a bee or wasp nest in it, some dryer sheets won’t be enough to remove it. You’ll need to call a professional for that.

Still, the fact that dryers sheets are an effective preventative measure for this kind of stuff is fascinating. Who knew?