(CNN) -- The jailhouse talk gets to the point.
"My name is Wayne Kramer."
"Hello, Wayne," inmates say.
This greeting, an echo from an Alcoholics Anonymous meeting, marks the start of Wayne Kramer's recent visit to the Los Angeles County Jail. He's been in and out of dozens of jails and prisons all over the United States for his charity, Jail Guitar Doors.
Kramer and his musician friends are playing a brief concert for about 100 inmates. When they're done, they will leave behind musical instruments that will be used in song writing workshops for the detainees.
Kramer tells his captive audience that the donated guitars are tangible proof that people on the outside care about them and believe in them.
"The guitars are not gifts," Kramer tells his audience. "They are a challenge to you."
The message is nothing they haven't heard before, but they listen to Kramer because for a time, back in the 1970s, Wayne Kramer was also known as inmate 00180980 at the federal prison in Lexington, Kentucky.
He has been one of them.
In the late '60s, a teenage Kramer earned near-legendary cult status as guitarist for the Detroit hard rock band MC5. Their shows were notorious for a savage stage presence and their radical, even revolutionary, political agenda. It was a combination that would have a profound impact on bands that followed in their footsteps, even after the MC5 had largely faded from public memory.
"The band MC5 were the forerunners of punk rock," says Tom Morello, lead guitarist of Rage Against the Machine. "They also injected radical politics into music -- something I know a bit about myself."
But MC5 started to fall apart by the early '70s. Kramer's life became in a downward spiral fueled by cocaine and booze. He started selling drugs on the side. His final sale was to an undercover FBI agent and resulted in his stretch in a federal pen.
Kramer's fall inspired the famous punk rock band The Clash to write a song about him called "Jail Guitar Doors."
"Let me tell you about Wayne...and his deals of cocaine," says a lyric, written by The Clash's Joe Strummer and Mick Jones.
In turn, the song title later inspired the name of Kramer's charity, he said.
His time in the pokey was back in the days when U.S. drug laws were much less harsh that they are today. Kramer's offense earned him four years in prison at the time. Today he would receive a life sentence. But he says today's harsher penalties are a failure.
"This war on drugs has been going on for 30 years. And we can go out on any street in America and buy better quality, cheaper heroin and cocaine today than we could 30 years ago," he said.
He contends the whole criminal justice system needs to be reformed.
Kramer believes that music and the arts can be a powerful tool in helping inmates find redemption and a better way to live when they are released from prison.
Having a guitar during his own prison term helped Kramer survive.
"The environment of prison is designed to strip self-respect from you," he says. "Strips you of your dignity. Tells you, you have no value in the world. Being able to create art, to make music, says, 'Hey, I do have value here.'
"I'm an ex-offender, and I'm a musician," he continues. "Maybe I could serve as some kind of bridge there. Some kinship to the tens of thousands, and then the hundreds of thousands, and now the two-and-a-half million people just like me that are serving time in America's prisons."
The concert in the LA County Central jail is drawing to a close. The song choices send a definite message: "You Can't Always Get What You Want," and "Ain't No Sunshine When She's Gone."
The inmates sing along softly to the acoustic arraignments.
Today Kramer spends most days in a small recording studio where he creates scores for TV and movies. But he still takes the stage from time to time. The aging guitar player lacks some of frantic moves of his youth, but the fire still burns. He still plays a Fender Stratocaster painted with the stars and stripes. But now the guitars are manufactured in limited editions, the "Wayne Kramer Model."
In his hands the music shifts restlessly through contrasting styles. One minute Kramer weaves a funky groove, then slowly morphs into an acid-inflected jazz solo that spins towards dissonant chaos. A series of blazing power chords pulls everything back to basics, followed by a lightning torrent of screaming notes machine gunned into the night.
Wayne Kramer isn't mellowing as he ages. Not even a little.
CNN's Michael Martinez contributed to this report.