I picked this lens up last year, attached to a 1955 Canon IVS rangefinder camera.
The internal glass had become very hazy over time, due to a "backyard mechanic"
applying oil to the aperture blades. Today I dismantled the entire lens and gave
it a good cleaning. It still has some cleaning marks on the front element, but
they don't affect the image quality if I don't shoot directly into a light source.