We often say that there is no remedy for Mahapapam/Panch pahapapam, but the Ramraksha Stotra and Shree Ganesh Atharvasheersha both very clearly mention that reciting them would help us get rid of the sins.
Following is the excerpt :-
Rama Raksha Stotram, right at the start mentions (Translation from Hindupedia -
Charitam Raghunathasya , shata koti pravistaram
Ekaikam aksharam punsam, mahapataka nashanam
The story of Rama is written in four billions words, But reading even one letter of that, destroys all great sins.
Similarly Shree Ganesh Atharvasheersha mentions Translation from greenmesg.org–
Etadarvasheerha yodhite, sa brahma bhuyaye kalpate,
Sa sarvatah sukhmedhate, sa panch maha papat pramuchayate
He who studies this Atharvashirsha (with Shraddha), will become fit to realize Brahman,
He will not be (permanently) tied down by any obstacles (and his consciousness will become clearer), (Permanent) Happiness will increase within his consciousness, wherever he is (i.e. at all times),
He will get freed from the five grave Sins (the memory of sins tend to create permanent obstacles within the consciousness for the jivas to sense the Paramatman),
So if one has indulged in a maha pataka, can reciting these mantras or reading and listening to the stories help get rid of the sin?