Clean a Wacom Intuos mouse

Step 3 ...and a haircut.

Now the mouse should be a LOT more sightly. You can use an X-acto knife or something pointy and sharp to carefully clean out the junk along the edges of the felt. Once again, don't push down too hard or you'll cut the plastic.

Then, depending on how obsessive-compulsive you are, you should be done with the bottom of your mouse.