All you need is a bad clicky mouse, like the one pictured, a phillips screwdriver, and a nail file.
Step 2: Take the top off
Step 3: Remove the buttons
Step 4: Chck it out!
If you look at the back of the buttons you'll see some little indentations. These are caused by constantly being crushed into the little actuators inside the mouse by ham fisted, computer illiterate, college "students," whose parents money would have been better spent renting them an apartment in Mexico and sending them daily beer deliveries. These also are the root of the clicky-no-clicky problem.