Determine the species of snake you are faced with before you try to take lethal action against the snake. Consult a book on snake species, take a photo and load it on an Internet snake forum or describe the snake to your local wildlife agency for identification assistance. Find out whether the snake is poisonous, or whether it may be an endangered or protected species in your particular area. Check to be sure it is legal for you to kill the snake. Call your local wildlife preservation or rescue association to request assistance with removal or extermination, if necessary.
Wear protective clothing whenever you are attempting to exterminate a snake. Even non-venomous snakes can bite you and cause a puncture wound in the the skin that may become infected and cause illness. Put on heavy duty waders if you have them, or layer several pairs of long pants in heavy-weight denim along with leather boots and long-sleeved shirts or jackets to protect yourself from head to toe. Wear protective gloves and eye-wear whenever possible.
Corral the snake into an accessible area if possible. Remove any large items or debris such as stones and logs where the snake may retreat and try to hide from you. Use a long stick or the handle of a shovel to coax a snake out of an existing hiding place into an open where you can gain better access. Exercise extreme caution and avoid handling the snake. About 80 percent of snake bites are reported to occur when individuals are attempting to handle or move a snake for extermination.
Employ your extermination method once you have gained access to the snake. Use the blunt edge of a metal shovel to cleanly sever the snake's head in the most humane manner possible. Drop a heavy rock on top of the snake to crush it, or shoot the snake with a rifle or revolver.