This one is from How to Avoid Purgatory by Paul Sullivan
"**HOW POPE PIUS IX CURED A BAD MEMORY **
The venerable Pontiff, Pius IX, appointed a holy and prudent religious named Padre Tomaso to be bishop of a diocese. The priest, alarmed at the responsibility put upon him, begged earnestly to be excused.
His protests were in vain. The Holy Father knew his merits.
Overcome with apprehension, the humble religious solicited an audience with the Pope, who received him most graciously. Once more he pleaded earnestly to be excused, but the Pope was immovable.
As a last recourse, Padre Tomaso told the Holy Father that he had a very bad memory, which would naturally prove to be a grave impediment in the high office put upon him.
Pius IX answered with a smile: "Your diocese is very small in comparison with the Universal Church, which I carry on my shoulders. Your cares will be very light in comparison with mine.
"I, too, suffered from a grave defect of memory, but I promised to say a fervent prayer daily for the Holy Souls, who, in return, have obtained for me an excellent memory. Do you likewise, Dear Father, and you will have cause to rejoice. "
The prayer which I normally use while driving or otherwise during the day is the one Our Lord dictated to St. Gertrude the Great to release 1,000 Souls from Purgatory each time it is said.
“Eternal Father, I offer Thee the Most Precious Blood of Thy Divine Son, Jesus, in union with the masses said throughout the world today, for all the holy souls in Purgatory, for sinners everywhere, for sinners in the universal church, those in my own home and within my family. Amen.”
Hope that this helps, the holy souls are great intercessors as Fr Schouppe refers to in one of the many visions related in the Dogma of Purgatory specifically if I remember correctly St. Margaret Mary “ingratitude is unknown in Purgatory”
Best of luck