Place an empty cardboard 10-pack juice pouch box on a table. Measure 6 inches from the bottom of the box. Draw a line to follow when you make the cut. Cut the box with a box cutter. Save the bottom of the box. Discard or recycle the top of the box.
Cover the outside of the box with a thin layer of liquid glue. Wrap the box in Valentine-themed gift wrap, smoothing the paper as you wrap to create a flat, even surface. Allow the glue to dry.
Cut a 4-inch slit in the paper that is covering the open end of the cardboard box. Trim around the inside of the "mail slot" with scissors until you are left with a half-inch opening.
Decorate the outside of the Valentine box with glue, craft foam hearts, sequins, beads and craft feathers and colored markers.