Washing is a gambling term that refers to an action practised by croupiers. Before leaving the table or before the next hand starts, dealers often rub their hands together to show the players their hands are empty. The term got its name because the movement of the hands resembles the act of someone washing their hands.
To become a dealer, a person must undergo special training where practices like washing are instilled into dealers’ routines. Since casinos value transparency, they insist on their croupiers to follow strict policies so you will often see croupiers “washing their hands”.
Additionally, dealers often do card washing, which is a shuffling technique they have to use. Before shuffling the cards, dealers will spread all the cards on the table and move them randomly, as if they were washing them.