There is a Chaplet for the Holy Souls, Which, whenever I have prayed it, proved to me beyond doubt by special graces recieved, that indeed they are aware, grateful and helped by all our prayers.
One Grace in particular is the occasions when past, forgotten sins are brought to mind… and you can immediately offer a prayer in atonement for it, to repent of it. Also, you can learn from past mistakes with this same help. This is the Chaplet that has proven so effective, why not give it a try.
On the beads of the Rosary, starting and ending with prayers that suit you, such as Glory Be, Hail Mary or Our Fathers;
Large Beads: O poor souls, draw the Fire of God’s Love into my soul, to Reveal Jesus Crucified in me, here on earth rather than hereafter in Purgatory
Decade Beads: Crucified Lord Jesus, Have Mercy On the souls in Purgatory.
–mediating on the Passion or the Wounds as well, as with other Chaplets
Also you can offer that decade prayer throughout the day

there were times when God drew me to pray it, once when I was just doing my shopping, -so by that I know that it is helpful.
GOD BLESS YOU ALL