You don’t always need an envelope or a box to send something through the U.S. Postal Service. As long as it’s clean, durable, and clearly labeled with the recipient’s address, you can stick postage directly onto surprising items—think rubber ducks, beach balls, skis, hula hoops, bricks, coconuts, potatoes or even a single flip-flop. 

The secret is meeting the USPS size and weight requirements (minimum 5″ × 3.5″, maximum First-Class Package up to 13 oz), using a permanent marker or adhesive label for the address, and affixing the correct postage. 

Postal clerks may raise an eyebrow, but novelty mailings like these have made their way coast to coast, avoiding any extra packaging. Think that’s strange? One family mailed their 5-year-old.