Never open clams with a paring knife or other sharp instrument. You can cut yourself badly. It's best to use a flat knife made for opening clams or some flat kitchen knifes may do the trick. Use a thick towel, glove or pot holder to protect the hand that is holding the clam. Hold the flat knife in your other hand, pull the shell opening towards knife until it penetrates between the shells, then stop. Simply rotate the knife to pry open the shell. Fresh clams open easier when they are cold.