Poche, thank you for bringing the Heroic Act of Charity to attention again. This is the information I have in my files. I apologize that I don't have the source.
What is the Heroic Act of Charity?
There are heroes in the Catholic Church - they are the canonized saints.
It is true, that all people who enter Heaven are saints, but the canonized saints have done something that is extraordinary and have been made role models for future generations of Christians. All of us can become heroes while on earth. It won’t necessarily lead to our canonization, but it would definitely help those in need and also bring us closer to Jesus. An opportunity has been given to us by the Church to help the souls in Purgatory. It is the Heroic Act of Charity.
Through the Heroic Act, we give all of the indulgences from our prayers, our sufferings, and our works of charity for the benefit of the souls in Purgatory. Also, the indulgences from the prayers offered after your death will go to the souls in Purgatory. Even though we give the Holy Souls the value of our indulgenced acts, we still keep the blessings of what we have done which will bring us glory in Heaven.
The Heroic Act of Charity has been approved by Popes Benedict XIII (1728), Pius VI (1788), and Pius XI (1852). The Sacred Congregation of Indulgences made a decree regarding it on December 18, 1885 and it was confirmed by Pope Leo XIII the next day. Many Christians devoted to the Blessed Virgin Mary, make it a practice to deposit the said merits and suffrages into the hands of the Blessed Virgin that she may distribute these favors to the souls in Purgatory according to her own merciful pleasure.
If you would like to make the Heroic Act, you can offer the indulgences of all your prayers, your works of charity, and your sufferings for the benefit of the souls in Purgatory. This includes the benefits of all of the prayers said for you after death. If you have a problem with saying this in your own words, use the following prayers:
O Holy and Adorable Trinity, desiring to aid in the relief and release of the Holy Souls in Purgatory, through my devotion to the Blessed Virgin Mary, I cede and renounce, on behalf of these souls, all the satisfactory part of my works, and all the suffrages which may be given to me after my death. In their entirety, I offer them to Mary, the Most Holy Mother of God, that she may use them, according to her good pleasure, for those souls of the faithful departed whom she desires to alleviate their suffering.
O my God, deign to accept and bless my offering which I make to Thee
through the most august Queen of Heaven and Earth. Amen.
Lord Jesus, King of infinite Mercy, I give all of the indulgences that would have been mine through my prayers, acts of charity, my own sufferings, and for the prayers said for me when I pass into eternity to free my brothers and sisters from the pains of Purgatory. Have mercy on them and bring them into glory
in Your eternal presence in Heaven. Amen.