There is no "closely guarded secret" to lens coating. It is a common process; Monophoto's description gets at the crux of it. There is no problem with cleaning a coated lens. The coating is harder than the glass. That's why they apply coatings to eyeglass lenses, cell phone displays and numerous other transparent plastic items now, that would otherwise get scratched to heck in no time. Just be careful to blow off any sand or dirt before you wipe the lens.