There is dust inside my screen...
First, you should find out whether the dust is on the inside of your screen, or if it’s just stubborn dirt on the outside.
Try breathing onto the screen, then wipe it clean with a soft micro-fibre cloth.
If this doesn’t help and it significantly interferes with your enjoyment of the system, we’ll happily clean your Nintendo DS. There will be a charge, and details of these costs can be found on our guideline prices for out-of-warranty repairs page.