I have a Nikkor 55mm 2.8 micro lens with clean and clear optics but that has somewhat stiff focusing and apperature blades that are "stuck". The blades are clearly dirty. I have removed the lens mount but I am unable to get the rear lens element off to perhaps start cleaning.
There are two holes in the rim of the rear lens element "housing", but using a pointed spanner wrench gets me nowhere (clockwise or counter clockwise).
As I remember this lens, if you remove the lens mounting flange you can access the srews (3 that hold the lens assembly into the mount--with that out you can remove the rear lens assembly and then the blades.