Catholics can obtain plenary indulgences for the deceased from November 1 to November 8

The Vatican's Apostolic Penitentiary states in the Handbook of Indulgences that the faithful may obtain a plenary indulgence for the departed every day from November 1 to November 8. This eight-day period relates to the ancient observance of an octave for All Saints' Day, a practice established by Pope Sixtus IV in the 15th century.

A plenary indulgence is the remission of temporal punishment for sins that have already been forgiven. To obtain this grace for a soul in purgatory, the faithful must be in a state of grace, have an interior disposition of complete detachment from all sin, receive the sacrament of confession, receive the Eucharist, and pray for the intentions of the Holy Father.