Before you start boiling, you'll need to prep your crab for its big bath. This involves rinsing it under cold water, and then submerging it in a pot of saltwater that's been heated to a rolling boil. Make sure the water is deep enough to cover the crab, or you'll end up with a half-cooked crustacean.
Now, here's where things can get a bit tricky. You see, crabs are naturally talented escape artists, and they will try to make a break for it if they get the chance. So, make sure you've got a secure lid on that pot, or you'll be chasing after a crab on the loose!