This is what Major League Baseball has been using to rub up baseballs before games for nearly 75 years. Why would they want to play with dirty baseballs? Well, I can tell you from first hand experience, brand new baseballs are slick, which makes it hard to grip, pitch, and throw them. Even though I don't play anymore, I'd still like to have some of this as a collector's item. They even did an episode of "Dirty Jobs" about this mud.