Guys, Getting really irritated by the greasy streaks left on my screen caused by the smart cover (for those unaware of this issue, read here: http://www.cultofmac.com/ipad-2-smart-cover-leaves-greasy-streaks-review/86595). Does anyone know of a good way to keep your screen clear of these? Would a screen protector work? I don't know what causes this, and how to avoid it. Any ideas?