The St. Gertrude Prayer for the release of souls from purgatory: 

Pray this prayer often as you can to help release souls from purgatory and in return they will pray for you from Heaven. This truly the unseen love and spiritual work for thy neighbour.

​
“Eternal Father I offer you the most precious blood of your divine son Jesus, in union with all the Masses said throughout the world today, for all the holy souls in purgatory, for sinners everywhere, sinners in the Universal Church, those in my own home and within my family. Amen.”