When buying clams, make sure the shells are all tightly closed. If the shells are gaping slightly, tap the clam and it should close. If it doesn’t, it’s dead and must be thrown away. Clams should be stored in the bottom of your refrigerator, where they will keep for 2 days. We like to soak the clams overnight in salted water to get them to expel any sand and grit trapped inside their shells.