After realizing that there was a way to take the cover offa my polk monitors, i saw it was kinda dusty. i tried to brush some off, but there was a layer that stuck. Is there a better way? this also helped the sound a bit.

Secondly: I accidentally started a cd at WAY past normal volume. I quickly turned it down, but that makes me wonder: how loud can I make my speakers before they blow out? How do i know that they have/are close to doing it?
thanks for helping a newbie