Some of the better-known ways of cheating in baseball:
DOCTORING THE BALL
How It's Done: The list of foreign substances that might work is almost limitless. For Garrett Broshuis, who pitched in the minor leagues for six seasons, a little spit might have made a big difference — but he says he didn't use illegal pitches in games. "I messed around with it in the bullpen a little bit," he said. "The bottom was falling out of the thing." Broshuis later wrote a paper on cheating in baseball while at the Saint Louis University School of Law. In that piece, Broshuis recalls a coach who said he'd used all sorts of deceptive tricks when he played: "He would place Vaseline on his belt, rub soap on his undershorts (sweat mixed with the soap during the game to make the side of his pants slick), and pine tar on the bill of his hat."
The use of pine tar is controversial. Some justify it by saying the substance doesn't really change the ball's flight — it just helps the pitcher with his grip.
A pitcher might also scuff the ball with sandpaper — if he can smuggle it to the mound without getting caught.
Famous Examples: Gaylord Perry may be the most notorious (and celebrated) practitioner of sneaky mound behavior. He won 314 games and made the Hall of Fame. In 1987, Minnesota pitcher Joe Niekro was suspended for carrying an emery board and sandpaper in his back pocket.
ALTERING A BAT
How It's Done: Derek Zumsteg explains this in great detail in his book "The Cheater's Guide to Baseball." Cut off the end of a bat, drill a hole in it, and fill it in — with cork, for example. The idea is that a lighter bat will increase bat speed.
Famous Example: In 2003, Sammy Sosa broke his bat in a game and was ejected when umpires found cork inside. Sosa said he used the corked bat to put on fan-pleasing shows in batting practice, but erroneously used it in a game. He served a seven-game suspension.
How It's Done: How isn't it done? A team might try to steal the catcher's signals for what pitch is coming, for instance, and a baserunner on second should have a nice view. As Zumsteg's book points out, what's really looked down on are people stealing signs away from the field — from the stands, for example. Coaching signs, such as instructions to basebrunners, can be tough to decode, but there's a way around that. Zumsteg: "Ignore the coaches with their long, complicated routines and watch the players receiving the signs. It's like poker players reading tells."