Chief Keef has revealed that he has officially quit drinking lean. In an interview with Billboard, Keef said, “My last two mixt apes were mistakes. I was on promethazine, all drugged out. I was tweaking. I don’t sip the lean no more though.”Meanwhile, according to his rehab center director, Keef is making god progress, saying, “His recovery is moving in a very positive direction. I think he’s ready to move forward. He’s a very kind young man.” Keef has been in an ORange County rehabilitation center.