I would use non abrasive windex. Any old solution won't do because of ammonia. alcohol, etc. I believe. Some LCD cleanser will do the trick, or if you use glasses just an old lens pad that has solution in it!
I bought an eyeglass cleaning cloth at a local drug store. If there's something on it being particularly stubborn I will fog the screen a bit with my breath and then use the cloth. I haven't used ANY cleaning solution and I can get my screen like new with the above procedure.
Just use a microfiber cloth. Don't use any liquid or windex on it, just the cloth. It will remove the oils from the screen. Liquid inside the phone can be damaging to the components inside, not to mention certain liquid cleaners are abrasive and can damage your screen over time, creating pits and unevenness in the glass, which I'm sure on a touch-screen device will cause you more headaches then you wanna deal with
ya, the micro-fiber cloth idea is the way to go. IF you can't get something off with just the cloth and a fogging with your breath, place just a drop or two of Windex ON THE CLOTH - NOT ON THE SCREEN, and use that. You could also use a drop of Windex or ammonia on a Q-Tip.
Cleaning the screen of this device is only slightly less sensitive than cleaning optics on a good telescope. You absolutely don't want any cleaning liquid to get past the edge of the screen. So go easy and get it clean.
I cleaned my screen VERY thoroughly before I put a screen protector on it, and now I STILL just use the micro-Fiber cloth with a tiny drop of Windex to clean that.
