[Constant (David)]

Originally Posted by Rocket

Another approach to cleaning optics, at the other end of the temperature scale, is CO2 "snow", eg https://www.co2clean.com/telescopes . I think this is mainly used for large mirrors, for example in observatories where the effort to remove and realuminise a mirror is considerable, but it is used for a wide range of sensitive surfaces, including semiconductor wafers.
Opticlean is another way to clean optics, but it can wick under the edges of elements and onto the lens holder, making it hard to completely remove - more informatiuon here https://www.cloudynights.com/article...opticlean-r539
Cheers, Ed

Many thanks!

David