Dirty job: How NASCAR's Bristol Motor Speedway was converted from concrete to clay
Spring cleaning is coming late to Bristol Motor Speedway again. (David J. Griffin/Icon Sportswire via Getty Images | Jared C. Tilton/Getty Images) For the second year running the half-mile oval in Tennessee has been temporarily turned into a dirt track for its spring NASCAR weekend. 2,300 truckloads of clay need to be hauled into the…