well, I'm not sure about the solution, but I would go with some sort of disposable microfiber cloths to clean. something you could use once, which would be guaranteed not to scratch your optics, that you could dispose of afterwards, so that the next one wouldn't ruin your optics either.
Of course, sealing your optics would help with this, but I think a Scratch-free solution is what we all want.
P.S: I am a newbie, and not sober (read: inebriated) at the time of posting, so many observations and thoughts are clearly overlooked. feel free to correct/ratify/smack me down at will.
"TO DO IS TO BE" - Nietzsche
"TO BE IS TO DO" - Kant
"DO BE DO BE DO" - Sinatra