Croupiers are required to "clean their hands" in all self – respecting gambling institutions. This is a standard gesture designed to show that the dealer is working honestly and does not try to deceive the casino or visitors.
Clearing Hands – visual demonstration by the dealer empty hand.
When the croupier "cleans his hands", he shows his open palms and it's like wiping them together.
This is a mandatory procedure for the dealer. With her help he shows that he did not hide chips, money or cards.