A sharp kitchen knife makes a poor and dangerous substitute for either of these tools. Some shuckers wedge a church-key type of can opener between the shells to pry them apart, but the opener's sharp tip can cause injuries if you're not careful. Pry Shells Open with a Push, a Twist, and a Little Muscle Shellfish open most easily when they're cold. Keep clams and oysters refrigerated until you're ready to shuck, and begin by scrubbing the shells clean under cold running water. Discard any that aren't tightly closed.
Clams are easier to open than oysters.
Their shells allow you to slide a knife between them without having to twist or pry your way in. Hold the clam firmly in the palm of your towel-covered hand. You'll notice that one side of the shell flares out slightly. Insert the knife at that point, force the blade between the shells, and pry them open. Once you've opened the clam, cut through the muscles that hold the meat to the shell.