There's a grease called "Krytox" that is designed to not outgass. In my Nikkor lenses, the grease is nowhere near the diaphragm, unless you apply it with a grease gun. Other 35mm lenses may or may not be arranged similarly. I've had no trouble with the lithium grease hazing the glass, but I've only been using it on helicoids for about 13-14 years. The brand I have isn't Lithease, it's an instrument type grease. Again, in my lenses, the helicoid is far enough from the glass that it may not be a problem. I think perhaps the most important thing is, not to apply too much. Some lenses I've had apart are greased up like a wheel bearing.
Originally Posted by Nicholas Lindan