Why ‘Purify’ the Chalice?

“Purification” refers to making sure no eucharistic elements remain in the sacred vessels, whether under the appearances of bread or wine. This is done out of great reverence for Christ’s sacred body and precious blood.

After the Communion rite, a priest or deacon gathers and consumes any fragments remaining from the consecrated hosts. Then, using his hand, a priest or deacon transfers to the chalice any small particles of the hosts remaining in the ciborium or on a paten.

Water is then added to the remaining eucharistic elements in the chalice, typically with the assistance of an altar server, purifying in the process the priest or deacon’s fingers that have handled the consecrated hosts. A priest or deacon then consumes the remaining eucharistic elements in the chalice.

Then the priest or deacon uses a purificator to remove any eucharistic elements that remain in the chalice. The purificator is cleansed after Mass, often by a sacristan, and the diluted elements, which no longer contain the Real Presence, are poured down a sacrarium that takes the solution directly into the ground rather than the local sewage system, a further homage to the substantial Real Presence that once existed under the appearances of bread and wine.

For more information on the purification of the sacred vessels, see this answer by Fr. Charles Grondin.