Cleaning the AR inside of watch case/crystal

[processengr 13,328]

Question for those who have been there, done that...@ncrich, @gentle 

Have the LMPO open for crown/tube change, red second hand mod. What is preffered way to clean crystal? I have tried eyeglass cleaner with eyeglass wipe, but not in Nirvana yet...

[Glaude 1,615]

I use that sort of stuff : 

https://www.lenspen.com/

Works great (even the cheap one you can find everywhere).
First you brush the inside to remove any debris that will potentially scratch the glass, then you use any cleaning solution for spectacles or screen with a microfibre cloth and in the end you finish with the lenspen carbon tip.