From the Manual of the Purgatorian Society:
ANNIVERSARY OF “ALL-SOULS.”
The anniversary of "All-Souls" was instituted by the Church as a day of special prayer for all the faithful departed who are as yet deprived of the blissful contemplation of God, and the possession of Heaven. These holy souls endure most agonizing torments, and count the lingering moments of time, while awaiting release from prison, or, at least some relief in their intense pain. They have special confidence in their friends and relatives upon earth, hoping to be lovingly cherished in their memory, and aided by their fervent prayers. With holy Job, they cry out: "Have pity on me, have pity on me, at least you, my friends, because the hand of the Lord hath touched me." (Job xix.21.)
The anniversary of All-Souls should serve to revive and confirm our devotion in behalf of the suffering souls in Purgatory, and induce us to make ample amends for our neglect of this duty during the year. "A gift hath grace in the sight of the living, and restrain not grace from the dead."(Eccl.vii 37.)
Prayer: O God, Creator and Redeemer of all the faithful, grant to the souls of Thy servants pardon of all their sins, that by pious supplications they may graciously obtain the remission they have always desired. Who livest and reignest world without end. Amen.
Special Intercession: Pray for the souls of those who suffer the greatest torments.
Lord grant them eternal rest and let perpetual light shine upon them. May they rest in peace. Amen. (Three times.)
Practice: Examine how often and in what manner you have practiced prayer for the souls in Purgatory.
Invocation: My Jesus, mercy!