Manson wrote in the will that his wishes for his death had been stated to the pen pal, though his body is still with the state of California, six days after he died.
If it is not claimed after 10 days, it will be cremated by the state.
Later in the will, Manson noted: "I'm not in the best spot to rest in peace."
Manson was making money of his likeness while in prison, with a New York Times article revealing in 1993 that the man who convinced his followers to embark on a two-night murder spree that left Sharon Tate and others dead was getting 10 cents for every $17 shirt sold at a surf shop in California.
The shirts showed Manson's face on the front and said "Charlie don't surf" on the back.
Manson also owned the rights to his music, though it is unclear if that "exclusive catalogue" includes the Beach Boys song Never Learn Not to Love, on which he was an uncredited writer.
He wrote in the will that there are over 100 songs that he owns the rights to, though he did not name any of them in the document.
Manson identified himself as a "single man" with two known children, sons Michael Brunner and Charles Manson Jr.
Brunner, who was named Valentine Michael Manson at birth, is still alive and has no association with his father, having been raised by his grandparents after his mother Mary was arrested along with other members of the Manson family.
Mary served a brief sentence for credit card theft and forgery before moving back to Wisconsin.
She was present the night that Gary Allen Hinman was murdered, but played no role in the actual killing of any individuals.
Charles Manson Jr committed suicide in 1993 at the age of 37, with the cause of death a self-inflicted gunshot wound.
His son, Jason Freeman, is still alive, but never had the chance to visit his grandfather in prison.
The will was witnessed and signed by Roger Dale Smith, a fellow inmate who earned the nickname "pincushion" because he was stabbed so many times while in the custody of the California prison system.
It is not confirmed, but according to some he was stabbed more times than any other prisoner held behind bars in the state.
Smith was also once called "the most dangerous, most psychopathic inmate housed at San Quentin".