Cleaning of the gut cavity of gutted fish by hand with jets of water or by means of a mechanical washer prior to boxing. The bleeding and washing steps may be combined in a mechanical system. It may refer to the cleaning of iced fish or thawed fish in water to remove mucous, slime or loose scales prior to filleting, or to preparation for some other process such as smoking or canning, or to the cleaning of shellfish prior to shucking. It may refer to the removal of excess salt from dry salted fish prior to smoking. It may refer to the process of treating fish mince or minced fish with successive water and brine washes to remove soluble proteins, pigments and lipids during the production of surimi.