It's Opening Week for the Red Sox and major league baseball so NPR appropriately did a segment on Baseball Rubbing Mud.
"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?Secret ingredient? The owner only knows.
New Jersey mud."
"What counts is that the muck, described as resembling a cross between chocolate pudding and whipped cold cream, really works!"Read or listen to the NPR segment here.