Got a slight issue with my original ds. After long periods of stylus heavy play , the screen seems to get some sort of residue left behind.It's quite annoying as it gives the screen a different feel. It comes off easy enough with a damp cloth , but it's quite annoying having to keep cleaning it. Seems like I'm constantly doing it , but at a guess i'd say after every 10 or so hours of play. I have a hori screen protector on it , and it's a jap launch model. Not sure if it happened before I had the protector as I never really played much till recently. Just wondering if it's normal as I aint sure as I don't ever see anyone mention it anywhere , or if not , how to stop it happening. Here is a pic The marks you can see cover the whole bottom screen , like I said above they just wipe off , but it's well annoying keep having to do it .