how to remove gritty sand from mussels before steaming
To remove grit or sand that may be under the shells, you'll need a pot big enough to hold the mussels. Dissolve about 1/4 cup salt in 2 cups warm water and then add 2 tablespoons cornmeal or flour. Add the mussels and enough cold water to cover them. Soak for 2 hours or overnight in the refrigerator. The mussels will actually take in the grain and expel the grit or sand.