Soak the mussels in clear water for about 20 minutes to allow them to breathe and clean themselves from their impurities.
If some mussels are opened, make sure they are alive by knocking on their shells with a spoon. If alive, it should close completely by itself. Discard of any open mussels remaining.
Discard of any mussels in the package that is chipped or damaged
Brush the mussels shells with the tip of a spoon to remove the sand, barnacles or any other attachments.
Remove the beard of the mussel, holding it in one hand, and grasping the beard with the other hand.
Rince the mussels under cool tap water and set aside.