Method – Discard clams which are open and soak them overnight in salty water (2 cups of water and 2 teaspoons of salt). Drain clams and put them in a pot, pour in dashi and simmer until clams open. Skim off foam from the surface. Add miso paste, mix gently to dissolve it in the soup. Serve.
Recipe from: http://www.opensourcefood.com/people/Paula/recipes/clams-miso-soup
Changes were made. http://creativecommons.org/licenses/by-sa/3.0/