Marines with Marine Medium Tiltrotor Squadron VMM-261 (Reinforced), 24th Marine Expeditionary Unit, clean an MV-22 Osprey aboard the USS Iwo Jima, Jan. 29, 2012, as the 24th MEU prepares for their final at-sea training exercise. The 24th MEU is conducting their Certification Exercise with Amphibious Squadron 8 scheduled Jan. 27 to Feb. 17, which includes a series of missions intended to evaluate and certify the unit for their upcoming deployment.