Charles Manson is now a model prisoner ... because wreaking havoc behind bars is apparently a young man's game.
Sources with the California Department of Corrections tell TMZ ... The soon-to-be 83-year-old murderer hasn't violated prison rules since February 29, 2016 when guards found him in possession of a cell phone. A big no-no.
Prison officials believe Manson's on a 20-month goody two-shoes streak simply because of old age and health complications.
But Manson has not always been a model prisoner ... far from it. TMZ's obtained Manson's rap sheet in prison ... and he's tested patience for decades. There are over 100 infractions that go back to 1972, including ...
October 1972 -- Refused to shave
July 1973 -- Assault on staff
January 1975 -- Spitting and threatening staff
June 1977 -- Striking an officer
July 1978 -- Assault on correctional officer
April 1983 -- Possession of marijuana
July 1985 -- Possession of a hacksaw blade
February 1993 -- Assault and battery on non-prisoner
July 1993 -- Possession of a stabbing instrument
April 1995 -- Trafficking narcotics
Sept. 1995 -- Threatening to kill a police officer
March 1999 -- Battery on an inmate with weapon
December 2003 -- Possession of a deadly weapon
June 2009 -- Possession of a wrist watch
June 2015 -- Refusal to provide urine sample