Here's a tip I discovered before touch screens were around and still use today. Meguiar's PlastX clear plastic cleaner and polish or the equivalent from your favorite brand. I don't know whether it has extremely fine glazing compounds in it, so I don't actually polish the screen with it. I just spread a tiny bit with my finger and wipe it off. That's it. It will keep your screen cleaner, slicker and help protect against scratching. I don't know how, but it does. It works on plastic and gorilla glass and doesn't interfere with digitizers that I've noticed. YMMV, especially between different models of phones. I've noticed that this works a little better on my Optimus 2X/G2X than on my ZTE Warp. And if you have a screen protector on, go for it - it can only polish it smoother! I use it on all kinds of things and I haven't had any problems with it over the years on anti-glare coatings on glass CRTs, plastic touch pads, or modern gorilla glass digitizers, but I am not responsible for any digitizer problems or phones that smell like cherries.