U.S. Marine Corps Lance Cpl. Barney Oldfield, a rifleman with Headquarters and Service Company, 3rd Battalion, 3rd Marine Regiment, uses a bottle cap to mark the location of a mock improvised explosive device during metal detector training Nov. 3. After departing from Hawaii from Oct. 27 through at Camp Dwyer, Afghanistan, Nov. 1, 2011.
(DoD photo by Cpl. Reece Lodder, U.S. Marine Corps/Released). Original public domain image from Flickr