Are We Keeping Our Optics Clean?

I have recently been in communication with Markus Ludes, of APM Telescopes, about the importance of keeping our optics clean. To an extent, I've followed the thought that unless it affects the view, leave it alone.

Some partial quotes from Markus (provided with his permission):

Contaminated with dew and dirt and such stuff starting to damaging coatings after 6 month. Lenses shall be keeped clean anytime , letting be lenses such dirty is terrible bad for optics. Advise for future , keep the lenses clean like eyeglases.

With 2 times per year good cleaning the lens can be new after 50 years of use , with no cleaning, dirt and pollen start to eat coatings after 1 year which is bad.

Markus advised soliciting comments/advice from Roland Christen, from Astrophysics, on this subject and asking for his recommended cleaning procedures. Roland?

As a group, are we keeping our optics clean and maintained? Sadly, in the past, I have not to a proper extent, but will be in the future.

Thanks
Steven Jindra

Hi Steven,
The problem with contamination is that living organisms tend to feed on them. This combined with dew is a deadly combination. The byproducts of the organisms usually are acids which etch the coatings in a very short time. I have seen some EPs that have been ruined in this manner.
I believe that dust is not too bad, but is it dust or pollen? If it is pollen then that is food, just add moisture and you have a Petri dish for growing mold and mildew.

Thanks for the wake up call Steven (thanks to Markus for the original thought)
I guess it is time for me to go back to my eyepieces and clean them one at a time, until they are all done... 8)

Acetone is an extremely powerful solvent. It is a component of model airplane glue and works by melting the plastic and when it evaporates the plastic is fused together. So I can't help but wonder what it might be doing to optical coatings. I prefer distilled water. The fumes are also dangerous.