Finding a dryer sheet tucked inside a mailbox can seem odd—especially if it keeps reappearing after being removed. While it might look like trash, it’s usually there for a very practical reason.

The Most Common Reason: Pest Prevention
Dryer sheets are widely believed to repel insects and small pests. Many people place them in mailboxes to discourage:

Wasps and yellow jackets

Spiders

Ants

Earwigs

Roaches

Mice or other small rodents

Mailboxes are dark, enclosed, and rarely disturbed—making them attractive nesting spots, particularly for wasps in warmer months. The strong scent and chemical compounds in dryer sheets (such as linalool and beta-citronellol) are unpleasant to many insects.

Why a Mailbox Specifically?
Mail carriers are frequently stung by wasps hiding in mailboxes, and homeowners or tenants may have already experienced this problem. Placing a dryer sheet inside is a simple, inexpensive, and non-toxic way to reduce the risk—without using sprays or traps.

If a tenant is doing this repeatedly, it often means:

She’s had a wasp nest there before

She’s trying to protect the mail carrier

She’s preventing bugs from crawling into her mail

She’s had pest issues in the past and is being proactive