This will teach you how to clean your Xbox 360 laser without taking it apart and voiding your warranty. I am not responsible for any damage that may occur if you don't follow this process exactly.
Step 1: Symptoms
The signs of your xbox's laser being covered in dust are that no disk will read through, if this is the case when you pop in a disk it will say reading and then say open instead of showing the game thumbnail.
Step 2: Supplies
You will need:
A disk you don't care about
Micro fiber cloth
Step 3: Cut Micro Fiber
Cut a strip of micro fiber roughly 2.5 inches wide and 5 inches long. Cut a hole in the center where to hold in the disk is. After this tape the cloth so it is secure. (Make sure to tape the longer ends on the graphic side of the disk so the tape doesn't touch the laser when inserted.
Step 4: How to Use
The first image shows how the disk would look if it were upside down( notice the cloth how it goes onto the graphic) the second image shows how it looks when it is in the correct position. The third image shows the disk in the correct position with the cloth on the graphic aligned with the tray.
Open your disk tray and insert the disk as shown. Open and close the tray 4 or 5 times to
Wipe the laser, one this is done place a disk in and see if it loads. This method is great, I was about to ship my Xbox to Microsoft, but then I cooked up this plan, enjoy!