cleaning a laser mouse
I have a laser mouse that worked very well. However, about a week ago the cursor started to move erratically. It was not moving smoothly.
The optical eye is dirty and needs some cleaning. Put a little alcohol (I used pálinka) on the tip of a Q-tip, and clean the optical eye gently. It solved the issue for me.
Here is a video of the cleaning process. The relevant part starts at 2:25.