USPS worker reveals why some mail carriers are leaving dryer sheets in mailboxes
"The mail carrier, who posted anonymously on Reddit last month, warned that 'if you randomly see a dryer sheet in the back of your mailbox, your mail carrier put it there for a reason' — and you shouldn't remove it. He went on to explain that bees — including Yellowjackets and wasps — like to make their homes in mailboxes, but scented dryer sheets have been known to ward them off, which can keep mail carriers from getting stung."