To store live, in-shell clams, oysters and mussels at home, be sure of two things: that they stay good and cold, and that they get plenty of oxygen. When you get home, take the shellfish from their bag or other wrapping and put them in a colander. Set that colander inside a large bowl, which will both catch drips as well as allow air circulation. Lay some dampened (but not dripping wet) paper towels over the shellfish and store them in the coldest area of your refrigerator (generally the lower back portion).

Be sure not to let the shellfish become submerged in fresh water, which will kill them. That means NOT on or under ice, which melts and collects below, possibly suffocating some of the shellfish. And don't be tempted to recreate a briny home by mixing salt into water. Clams, oysters and mussels will be much better off in the open air, but do plan on eating them within a day or two of purchase. Remember, any clams, oysters or mussels that do not close when tapped on the counter should be discarded before cooking.