why do you say that? It was S.O.P. to use q-tips (the long wooden type that came in sterile bags), acetone, and isopropyl alcohol to clean germanium coated laser lenses, and all manner of optics (coated and not), from night vision to spotting scopes to thermal sights. Then again, we also had a 3 months of optics training in which we learned the proper cleaning technique and how to disassemble, reassemble, and correct parallax issues.