If you’ve been lucky enough to snag a foul ball at a Colorado Rockies game, you’ve had your hands on a sacred ingredient of America’s pastime: mud. Lena Blackburne Baseball Rubbing Mud, that is. For nearly six decades, every baseball thrown in a major league game has been buffed with this particular brand of brown stuff, which is skimmed from the banks of a Delaware River tributary. Clubhouse attendants are usually in charge of rubbing down dozens of baseballs, which are pearl white and slick when they’re brand-new, before each game. The mud—which has a texture similar to cold cream—takes the sheen off the cowhide and gives pitchers a better grip. But don’t think there’s an unfair advantage (although the Rockies pitchers need all the help they can get heading into opening day this month); umpires check the balls before every game and toss out those with too much or too little mud.