Sometimes just labeling feelings helps. I journal a lot. I find it so helpful, and when I can read what I wrote, I learn a lot. I find walking helpful. When I do yoga, I get into a peaceful state, and I can meditate, and a lot of healing occurs. I think learning how to direct anger is important. such as "I am angry because ____. I would like _______." We need action when it comes to anger, but keeping in mind the serenity prayer "God, grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference." Learning that other people, places and things are not something we ought invest in changing, but to change our attitude, is empowering. We get frustated when we want to change something outside ourself, and it is usually futile. Keeping a gratitude list is helpful to keep me focused on blessings. Having a counselor, a sponsor, a 12 step meeting, support groups, a relationship with a higher power, give me a way to deal with feelings. I used to use drugs (pot) and alcohol to manage feelings. I used alone and drank socially. That didn't help me learn how to cope with feelings. It is a great skill to learn how to recognize feelings, honor them, find their source, express them safely, and get back to a healthy normal.

I like the idea of going to their grave site and directly speaking to them.

And if they were cremated and the ashes thrown into the ocean then go to the ocean and tell her that she can not hide from you or the past.

Also dealing with our own inner child is a way of addressing our own past feelings and emotions so that their power to harm us anymore from the past is taken away.

My therapist had me write down all the things that were good about my mother. What I had to be thankful to her for. What personality traits and looks, I attribute to my mom. Like my great legs! She was very smart and I think I have her brain. Things she taught me. Then I wrote her a letter of gratitude but I also told her I was sorry she was not her to share my life with me.
Then I had picture of her blown up to 8X10 and actually cut her fact out and made a mask out of it. One of my very best friends put the mask on and I read the letter of gratitute I had written to her. My friend responded for my mother. It was so healing - I didn't feel angry anymore. We held hands AND whenever I have something I want to talk about to my mom, my friend assumes the role again... it has worked wonders for me.
Sometime we confuse pain and sorrow for anger.
All my best.