passenger airbag door rattle

Hi folks - finally located a rattle I've been hearing for ages. Now that I know where it's coming from I was hoping I could fix it. With the car off, just sitting in the passenger seat if you touch on the dashboard on the airbag door or anywhere around it, the rattle noise happens. So just vibrations/bends coming into the cabin are setting this off. I was going to wedge something in to try and limit the noise but didn't find much luck. Wondering if others have noticed this (yes w/ the top down it's not an issue!) and had any ideas - 2000 Boxster
Thanks