A worm is a device used to remove unspent powder bag remnants from a cannon or other piece of muzzle-loading field artillery.[1] It usually took the form of a double or triple [2] corkscrew-shaped piece of iron on the end of a long pole that could be twisted down the barrel to pick up any debris left over from the previous firing of the weapon [3] [2] or used to extract a misfired charge.[2] It was usually turned twice before being pulled out.[3]
The worm during the civil war was either on its own pole hanging from the artillery carriage or attached to the end of the sponge. [2]