MacBook Pro black rubber screen edge

[insimbi]

I have an older Late 2008 MacBook Pro (unibody). The black rubber edge around the screen has started to turn grayish/white in the lower corners. Is this just from age, or can it be cleaned? I've tried to take some iKlear spray on a microfiber cloth to clean it. It seemed to help a little, but not much.

Anyone else have this happening?

 

[miles01110]

It's probably just normal dirt buildup.

 

[GuitarG20]

probably normal dirt buildup, and dirt is hard to clean off of rubber when it's rubbed in (it kinda is, since you close the screen onto the bottom case.