Former Soviet Union (FSU) lenses is an area we specialise in, partly due to their pedigree as many of them are copies of Zeiss wartime era lens designs. Often, when servicing FSU lenses, we dismantle the lens in its entirety, where all mechanics undergo ultrasonic cleaning and a multi stage polishing process.  Optics are bathed in a solution that cleans off all debris, fungus and other impurities, then the lenses are carefully reassembled, using new syntheitc greases. Lastly, the lens is collimated and adjusted for Leica rangefinder standards and verified further using a dedicated Leica digital M camera with EVF we keep on hand.