I really don't think that erasing certain memories is possible during our lives either unless we develop dementia (certainly undesired) and even then there might be flash-backs.

I think it's about working through the memories and events that cause us so much pain that will hopefully help. I am interested in what some of the others said above about EMDR work, as this has been suggested to me by my therapist too as an option to work through traumatic events of the past that had led to depression and anxiety.
I haven't done it yet, but will probably start with it soon. Maybe you could consider this as well. Or other ways and approaches in therapy?