Accessing Drivers in Sennheiser px 90: How do I do it?

[netufi]

I'm sure it's possible to take my Sennheiser px 90 headphones apart, but I'm not the most headphone smart person in the world, and I wanna be extra careful (especially since these are a gift and I really like them). I've seen a video or two of people just pulling off the plastic part that's under the cushion to get to the drivers, in headphones similar to the px 90's, and it seems like that's also the case with these headphones. But again, I'm a worry wart with these. I'm trying to remove hair from my drivers, because some heavier basses (eg. deep boom sound effects in movies) get really buzzy because of the hair (I know the headphones can handle such bass normally, it used to work). I'm quite certain it's the hair in them that's causing this, because occasionally I see hairs sticking out of the little holes in the plastic, and when I pull those hairs out, the bass gets less buzzy. I can see with close observation that there's a lot of hair under the plastic that I can't pull out. Any help is much appreciated.

 

[netufi]

Bumping with some images. Sorry about the quality, I only have my ipod camera. I don't know if I need to do anything with those little nubs that are on all 4 sides in order to remove the plastic. There aren't any screws.