Remove the beard, a fibrous appendage protruding from between the shells (Fig. 20.10). Do not do this until just before cooking, because it may kill the shellfish.
Mussels may be sandy inside if not commercially grown. They may be soaked in brine and flour or cornmeal like clams (see previous section) to rid them of sand.
Figure 20.10 When cleaning mussels, pull off the fibrous beard that extends from between the shells.