You can freeze steamers whole in a plastic bag without water after they spit. They will keep for a couple of months no problem, but not in a frost-free freezer -use a regular deep-cold freezer. Done right, they steam up just like the fresh ones. Just take a little longer.
Now, steaming clams is an art that many don't seem to get. Many people boil them in too much water, and\or drown them in wine. Best way IMO is a 1/4 inch of water with a few onions, a little celery, and a little garlic. Let the clams steam on high heat until the foam covers them all. Lower the heat but keep the foam over all of them while they cook. Once the majority fall from the shell they are done. Do not over-cook.
Have the garlic butter ready with a shot of worsheshire in it and a little parsley flake. The hot-sauce and ketchup nonsense people seem to push on this meal has no place here IMO. Clams dipped in garlic butter or their own nectar is the way to go. Drinking a cup of nectar with steamed clams is mandatory, and if you don't do that, you are a puss IMO.
Better yet is an traditional clam bake on the beach. I have only done it a couple of times, but this is the way to go if you can find the clams, time, and beach to do it on. Truly an art that is becoming lost in the traditional NW way. I'd sure like to do this a few times with some of the older folks who know what they doing. With 40 clam limits, you can hardly pull it off. But what a way to send a nice summer evening.
Additional recipes on this clam bake method would be appreciated...