Seen on Discover Channels "Dirty Jobs" and History Channels "Modern Marvels," Lena Blackburne Original Baseball Rubbing Mud is used by every Major League Baseball team on their new baseballs. Any knowledgeable baseball fan will tell you that the big league baseball teams never use brand new baseballs in a game. They’re too shiny to play with. So, what do umpires use to prep the balls and dull the shine? New Jersey mud. For nearly three quarters of a century, a special variety of Jersey mud, Lena Blackburne Baseball Rubbing Mud, has been removing the sheen from baseballs for just about every professional baseball team in the country.