Fixing My Mouse

I've been using Microsoft's Explorer Mini Mouse for just under a year and the middle mouse button started to become unresponsive to the point of being unusable. So I took it apart to see if it's a dust problem. After blowing a bit of the dust out of the mouse, it started working again albeit still a bit unresponsive. I've got to say, the inner workings of the mouse is quite impressive and interesting. Below are some pics.