I notice that at different points in the Mass, one of the acolytes pours water over your hands, with a bowl underneath. Is that for cleanliness…or what?
It is a ceremonial “cleansing”, really. Water, in the Church, is always highly symbolic. We use it for Holy Baptism of course. And, in the preparation of the Chalice for Communion, the Celebrant pours adds a small amount of water to the wine…signifying the humanity (water) that is mingled with the Divinity (Wine) in the One Person of Jesus Christ. The Holy Water stoop (the clear container available for parishioners to dip their fingers in as they come into the nave) contains Blessed water as a reminder of our baptisms, and as a holy seal upon our souls as we pray.
When the Priest who celebrates the Mass (the “Celebrant”) is about to begin the prayer of Consecration over the elements of Bread and Wine, he may say a prayer like this:
“Lord, wash away my iniquity; and cleanse me from my sin.”
This brief prayer sentence is a reminder to himself, and a confession before God that he- the Celebrant- is in need of purging of body/mind/spirit before presuming to stand in the place of Christ at the Altar. The water cleanses the fingers that will take up the holy Host and Chalice in the act of Consecration.
Again, when all the communions have been given, the Acolyte pours water over the Celebrants fingers to cleanse away any remnant of the Sacrament.