Dell 3100cn Color Laser Printer - Manual (Page 157)

5. Repeat steps 1 through 4 when inserting the remaining cartridges.
Cleaning Inside the Printer
A cleaning rod for cleaning inside the printer is installed on your printer.
1. Open the front door.
2. Pull out the slide bar that is inside the printer on the right side until it stops.
The access window cover slides open.
3. Hold the cleaning rod and push the rod in and pull out once to clean inside the printer.
4. Push the slide bar back to its original position.
5. Close the front door.