Remove the top cover, not the glass.
Just remove the four Torx screws, one in each top corner, and then lift
the cover off.
You may also be interested in this HP page, about cleaning in general.
http://h10025.www1.hp.com/ewfrf/wc/document?lc=en&cc=us&docname=bps02788
&product=58381&dlc=en&lang=en