Every baseball used in the American League, the National League, and most minor leagues is rubbed with Lena Blackburne Baseball Rubbing Mud before play:
It all began in 1938 when an umpire complained to Lena Blackburne, a third base coach for the old Philadelphia Athletics, about the sorry condition of the baseballs used by the American League. Back then a ball was prepped simply with mud made of water and dirt from the playing field. The result? The ball’s cover was too soft, leaving it open for tampering. Something was needed to take off the shine but not soften the cover.Blackburne took on the challenge. Next time he returned to his home in Burlington County, he checked out the mud along tributaries of the Delaware River until he found some muck (the whereabouts of the mud hole is still a dark secret) with a texture he felt would do the job. Taking a batch to the Athletics’ field house, he rubbed some balls with the stuff. It worked like a charm! What’s more, it had no odor and didn’t turn the balls black. The umpires were happy, and Lena Blackburne was in the mud supply business.