Laptop fan grille discoloration?

[darth_yoda]

So I have an Inspiron 7567 and recently I noticed something weird regarding the fan grille on the bottom. It is sort of discoloring. I have attached photos. Just wanted to ask, is this normal? I do game quite a bit, so is it due to the heat? I know it probably doesn't affect anything, just wanted to ask if anyone else has noticed it on their laptops.

 

[profoundnoah]

More than likely just due to heat. Couldn't imagine anything else being the culprit there.

 

[helpstar]

Should be dust, clean it with a q-tip. Don´t use vacuum cleaner or similar, could harm the laptop´s electronic if the fan spins and induces voltage by this.