If you don’t clean clams then you would taste very sandy clams. In order to remove sand from clams, there are two or three things you must do before cooking them.
First, wash them from tab water to remove outside of sands and dirt and pick cracked or broken ones.
If clam is opened, then tab its shell to see whether it is closed or not. if it is not closed then throw it away.
Second, With one gallon of fresh water, add 1 or 2 t spoon of sea salt and stir. Pour all clams and leave them into the dark place. Be sure the water temperature that should be around 40 degree that should cold enough.
Third, replace water after 30 min or 1 hour later for the next round.
Please make sure the water should be cold and located them into a dark place. Then, you will enjoy better taste of clams without any sand.