Yashica ML 28-85mm Teardown and Clean   View of the optical block from the side. Note the long threaded section with excess 'gunk', the screw-on edge cap at the rear of the block to further dismantle the group, and powder free latex gloves worn for oil-free/smudge-free glass handling. I applied 99% alcohol for grease removal on the threads to knock down further contaminations.