Old grease
Senior Airman Arnold Palmer, 62nd Maintenance Squadron aerospace maintenance journeyman, wipes the old grease off bearings and seals from wheel assemblies off a C-17 Globemaster III aircraft, Aug. 1, 2013, at Joint Base Lewis-McChord, Wash. Wheel and tire assemblies undergo a complete maintenance inspection every 120-days and are broken-down completely, cleaned and rebuilt. (U.S. Air Force photo/Staff Sgt. Jason Truskowski)