Rubbing alcohol on proper optical cloths.
Or pre-moistened optical cleaning wipes from Walmart $1.99 for 40, that's what I use for just about everything glass/lens I have, very handy moist towelette package format, and I can stack them everywhere without worrying about pouring on just the right amount of fluid and then cleaning a cloth, etc. Disposeable and biodegradable. 8)
I have a box at work, in the car, in the living room, and in my office (where my computers are [laptop goes from there to living room]). All this and I don't even wear glasses other than sunglasses for driving and skiing.
They are just very handy for all the 'screens' in my life.