Yup mine too, one grain of sand is all it seems to take. You could follow the path the single grain must have taken during a single commute. When the macbook is

Yup mine too, one grain of sand is all it seems to take. You could follow the path the single grain must have taken during a single commute. When the macbook is charging, a bit of static charge seems to build up on the screen, which can attract and hold small particles. Why did I get downvoted for this by the way?