I let my friend next to me use my white macbook and ask for a tutor to help her with a math problem on the laptop. When i got it back i saw ink lines and dots on it, stupidly the teacher pointed at the problems with his ballpoint pen. I did my best with the old fashion lick finger and dry off the screen but there are still bits of ink dots that are just annoying. Is there a substance or cloth of some sort i can use just to get rid of a few smudges and dots. They are minor but i want them off the screen. Thanks