This is very useful, Dom. Have you given any thought to putting information of this kind in a bound volume? Given the sometimes fugitive nature of information stored digitally, I'd be willing to pay to have this information in print form.
I have given it some thought, but I suspect the market for such a volume would be very small.
Nice but don't use paper lens tissue with methylated spirit on camera lenses and certainly not on surface silvered mirrors.
It is strongly recommended against by professional lens working people.
People get very worked up about specific techniques to clean optics!
But perhaps you should read the text more closely Andries. I recommended lens tissue and methylated spirit to clean the ground glass only, and only if blowing air doesn't work. This was a tip passed on to me years ago from Arri, but there are other methods and tricks to clean the delicate surface of a ground glass, such as using a clean putty eraser. For camera and lens optics I mainly use isopropyl alcohol and/or lens cleaner with tissues. Some folks like micro-fibre cloths or lens pens or pec pads, but lens tissues are also often used by professional lens people. You can fold them into a point for small optics like eyepieces or to reach an optic deep in a lens body. They can feel crepe papery but at a microscopic level they are non-abrasive.
The important thing when cleaning optics is to blow or brush off any particles first, and to make sure that the tissue, cloth, pen or pad you then use is clean.