Yankees legend Mickey Mantle once penned a handwritten letter pleading with kids not to abuse alcohol -- saying it wrecked his career -- and now the incredible note is for sale.
Mantle is one of the greatest baseball players of all-time ... he was a 20x All-Star, 3x AL MVP, and 7x World Series champion.
However, he also had a dark side ... battling alcoholism for decades. In 1995, Mantle received a liver transplant ... but only lived several months longer.
Now, an incredible note written by the Yankees slugger just hit the auction block at Lelands .