It's not really dirt on my screen but these white things that's all over my screen, I don't know what they are, but I can get it off. I use the microfiber cloth that came with my MacBook to take out any of my fingerprints and occasionally my saliva if it comes contact with my screen whenever I see them. Sometimes I use a damp Kleenex too, then the microfiber cloth. After 5 minutes or so these white spots appear on my screen, you can only see them if my MacBook is in sleep mode or off. I don't know what they are and I don't know what could've made them because I just cleaned my screen a few minutes before. And I'm tired of getting them off because they just keep coming back. And they're not from the Kleenex because sometimes I use the microfiber cloth alone. My MacBook has been only a couple of weeks old and I love it. And then I run into this issue today. I have stopped cleaning it for now.