A catcher's mitt is one of the most important pieces of equipment used on the field of play. They are moderately flexible when you buy them, and they can be used almost immediately without treating the glove. However, if you want it broken in to your own specifications, you need to take steps in order for it to be game-ready.
Squirt shaving cream into the pocket of your catcher's mitt. Rub the shaving cream into the pocket of the mitt thoroughly and then repeat the process. After you finish rubbing in the cream, take a towel and dry off the excess.
Place a baseball in the pocket of the catcher's mitt and close the glove as tightly as possible. Take a rope and tie the mitt in the closed position. Leave the glove in this position for at least eight hours.
Untie the mitt at the end of the eight hours and go out and play catch with somebody who can throw the ball fairly hard. A player who can make the glove pop every time you catch the ball will further soften the leather. About 15 to 20 minutes of playing catch should be sufficient.
Squirt glove oil in the pocket area of the mitt and rub it in thoroughly. Make sure there is no oil residue on the mitt. Take a baseball and put it back in the pocket of the mitt. Tie the mitt closed and leave it for another eight hours.