Clams are sold live in the shell, fresh or frozen shucked, and canned. When buying hard-shell clams in the shell, make sure the shells are tightly closed. If a shell is slightly open, tap it lightly. If it doesn’t snap shut, the clam is dead and should be discarded. To test a soft-shell clam, lightly touch its neck; if it moves, it’s alive.
Substitutes: mussel OR cockle OR abalone (tenderize first) OR scallop.