On a visit to her Florida kitchen, we noticed that Marcella Hazan stored the live clams she was going to use in one of her recipes tied up in a clean, damp kitchen towel set in a bowl in the refrigerator. Hazan explained that this method provides the kind of dark, cold, moist setting living mollusks prefer and helps keep them fresh. It's a great idea, and one that we've since adopted for oysters, too.