Food Network
Nearly all mussels available at supermarkets or fish markets today are farmed and not harvested wild. However, if wild mussels are available, the best way to rid them of sand and mud is to add about 1/4 cup of all-purpose flour to a large container of salted water. Then add the live mussels (which have not yet been debearded) and let sit in the mixture for 2 to 3 hours. The mussels will eat the flour and purge themselves of debris, as well as plump up. Remember that an open mussel that closes when pressed is good; if the mussel stays open after being pressed, it is bad and should be discarded.
