Use a wide packaging tape of at least 2″ to seal the opening of your box. Also use this tape to reinforce all seams. Only use clear or brown packaging tape, reinforced packing tape or paper tape. Never attempt to use cord, string or twine because they might get caught in shipping machinery and other equipment.
Make sure to use pressure-sensitive adhesive plastic tape as these don’t easily peel off and ensure that the package is well sealed. Apply at least three strips of this tape to both the top and bottom of the box.
When sealing boxes, distribute the tape evenly across flaps and seams, using the H taping method.
Never skimp on tape. You can never “over-tape” a package. More is usually better. Always remember that it is better to be safe and have your box overly secure than have it open in transit.