When bullets and cartridge cases are submitted for analysis, they should be individually packaged in their own canister, envelope, or other small container. Bullets (especially lead) should be lightly wrapped in tissue or cotton so that the bullet surface will be protected from possible damage. Do not mark or engrave any surface on a bullet or cartridge case as this may damage individual characteristics. If evidence must be marked, mark the container itself. Do not let any metal object such as forceps, knives or screwdrivers come into contact with a bullet. Metal objects will scratch the surface and alter the markings used for identification. Numerous cartridge cases recovered from the same area may be packaged together in one container to save time and supplies. Be sure to collect any wads or pellets in cases involving a shotgun. Under certain circumstances a wad can be matched to the barrel of a shotgun, especially if it has a sawed-off barrel. Film canisters or pillboxes make excellent containers for packaging bullets