Bob e-mailed the Kitchen Shrink to find out how to store and clean shellfish such as clams before cooking.
It is best to purchase clams just before cooking them so there should be little storage to worry about. Clams are purchased alive and must be kept alive. If you do purchase them several hours in advance, they should be kept cool and moist on ice or in the refrigerator. Don’t wrap them in anything airtight; they need oxygen to survive. Just before cooking, scrub them with a stiff brush under cool running water and trim off beards if they have them. If any are open, tap the shell. If they don’t close tightly, discard them. If any don’t open when cooked, discard them. All of the above goes for mussels as well.
A friend up here in Scarborough, Maine goes out and harvest clams He likes to clean and plump his clams before cooking. He leaves them in cold sea water in a 5 gallon bucket with corn meal. 12 hours later he changes the saltwater again and adds more corn meal. This gets the sand out of the clams and plumps them up. He shucks them and either steams or batter fries them. They are much better tasting. Hope you can try them.