Our Lord told St. Gertrude the Great that the following prayer would release 1000 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. Amen."
The above was taken from http://www.sufferingsouls.com/ site. Please take time to visit and pray for these suffering souls, who knows someday we may be the ones who are there and need prayer.