Applying Arctic Silver To An FC-PGA2 Package

[FPSguy]

I just received my Celeron 1.0GHz today. It comes in an FC-PGA2 package that looks like this. Do I need to worry about that hole in the lower-left corner? Can I just smear AS3 over it or should I avoid it with the AS3?

Also, I was just curious what the hole was for -- a temperature sensor or something?

 

[AndyHui]

The hole is supposed to be for air expansion. Just ignore it, and don't actually try to fill it up.

 

[BD231]

I find filling it gives me better temps