Shine and manageability.
Psst. Hey, guess what? Your laptop screen isn’t a touch screen. Oh, right, you knew that already. Well then, get yourself some Windex and a paper towel and—
Actually, ammonia will leave a film. And rough paper products will scratch the screen. Tissues are softer, but they’ll leave little bits of lint all over the place. And if your tap water has a high mineral content, it’ll leave mineral deposits.
So how can you clean your screen? If you have a few extra bucks to spare, buy a monitor-cleaning kit at your local computer store. If you’re cheap, make your own—half isopropyl alcohol, half distilled or purified water. Spray a small amount on a soft, cotton cloth and rub gently in a circular motion. If you’re cheap and lazy, wait until you’re wearing a soft cotton shirt and use your sleeve.
No joke—for a few fingerprints, it does the trick.