Installing a new dvd burner as mine has been broken for quite some time. And I figured since I am taking the front case off I may as well dismantle the whole thing and clean out everything. It was a nightmare, this computer is about 4 years old and I have only cleaned out the case twice. At quite a few points I found I was exchanging my dust remover for a damp wash cloth. My only regret is not taking photos.
The inside wasn't bad like this it was more of the faceplate that was like this. I clean the insides every year it's the faceplate I generally don't bother with.