First, be sure children and pets are clear of the work area, as curious kids, dogs, and cats are sometimes bitten while poking around or sniffing the carcass. Touching a ‘dead’ rattler can trigger a DEADLY fang reflex in the head (even if the head is separated from the body).
When you are ready to begin, use some kind of tool or jig and hold the snake head FIRMLY against the cutting surface to avoid “accidents”. REMOVE the head of the rattler by cutting it off with a sharp knife or meat saw. Venom is located inside sacs in the jaw, and injected into prey or predators via the fangs during a “bite”. Cut at least ½ inch behind the head, to prevent hitting a sac and risking exposure to the venom, which remains dangerous after the snake is dead. Dispose of the head in a prompt, safe and secure manner. Burning the rattlesnake head to a crisp in a hot fire, if available, is a good idea, which destroys the venom entirely. Otherwise multiple wraps of plastic bags and newspapers, and disposal into a trash can with secure lid, is advised.
Cleaning a snake is much like cleaning a very long fish. Except the snake may do a lot more whipping and thrashing about during and after the beheading, cleaning, and skinning phases (which can be a bit disconcerting!) Once things settle down, insert a knife into the vent area (waste orifice), and cut upwards toward the missing head, to the end of the skin. Remove entrails with your hand or thumb and/or spoon, and wash the body cavity out with cold running water. Scrape away remaining bits of innards while rinsing.
Care must be taken to clean the snake thoroughly. Always wash your hands with HOT soap and water after handling the rattler, which may – like poultry and other common meats – carry Salmonella. Snakes will tend to carry many pathogens on the skin, if they are infected, due largely to their intimate relationship with the soil. Proper butchering hygiene, soaking the meat in a salt brine AFTER skinning, and cooking completely will help ensure the meat is safe for consumption. (Even though medium rare snake meat is pretty darn good, its just not worth the risks!)
These procedures also reduce the odds that other parasites the snake may have on board will find you or your pets as a host. As far as wild animals go, snake is a pretty safe critter to eat, but it always pays to play it safe.
Make sure to check out rattlesnake skinning instructions, before soaking in a brine and preparing your delicacy for the table.