Use a sturdy and appropriately-sized shipping box or container that provides your items with at least a couple of inches of extra space on all sides, top and bottom for padding. If re-using a cardboard box, make sure that it is strong enough to support the weight of the product and will not cave in when heavy packages are placed on it.
Labels are not enough, you should pack your items properly so that even if the package is handled roughly, the contents will remain intact and will not cause damage to itself, other items in the box or its handlers. No amount of “Fragile,” “Handle with care” or “This side up” labels will prevent your package from being tossed, dropped, and mishandled during shipping. Bear these in mind when packing your sharp objects for shipping.
Wrap each sharp object generously with bubble wrap before packing it in the box. Make sure that the wrap will not unfurl during transit by securing it with tape or rubber bands.
For extremely fragile or dangerously sharp objects, it is sometimes best to double box them to give extra protection not only to the items but also to the shipping personnel that may get hurt in case of an accident.
Use a lot of packing materials so that the box is filled from top to bottom and sides. This will minimize or eliminate product movement. Items banging into each other inside the box is one of the most common causes of damage in shipping.
As much as possible, do not ship sharp objects together with items that can be punctured. If you really have to, make sure to wrap all items generously with bubble wrap. Sharp blades and pointed parts can be covered with cardboard pieces prior to wrapping so they will not cause any damage.
Never pack pressurized containers like aerosols together with sharp objects like darts and knives. Most pressurized containers are considered safety hazards which require their own special packing and shipping precautions anyway.