I was give a chunky lens some years ago, which had a little fungus growing inside.  This is quite a normal occurrence however some lenses are more prone than others.  I was reluctant to use it because I wasn’t use if this could spread into the camera.  In reality there are fungal spoors all around us and it is only when the environmental conditions are appropriate, that they grow.  The fungus in my lens seems to be quite dry now and I am going to attempt to clean it.

I rolled this Terence Mckenna anti haters mat to work on.

You can see where the fungus has grown on the glass the mirror of the lens.

I used a venire calliper to unscrewing the locking rings and popped the glass out.

To clean the inside of the lens, I use disposable lens wipes to start the process, and then cleaned the glass with methylated spirit and fabric glasses wipes.

I put on some art handling gloves and wipe off any remaining marks that I can see.  Occasionally I look through the lens at a light source to check if anything is still present.

I cleaned the foremost section of the rear but didn’t go any further as I couldn’t see any fungus inside.  There is a little dust particles in that section, which is normal for a lens that old.

I cleaned the inner mirror as I did the glass, and used some tape to pick up any fibers that had clung to the metal during the cleaning processes

Finally I used compressed air to pretty much blow anything out of the body and off the lens.

I popped the lens back in and fitted the locking ring.

Had I spent several hundred pounds on this lens I would have probably been more inclined to use a processional service.  But for my purposes this seems to be ok, and I am happy with the lens.