HP 6300 - Manual (Page 95)

To clean the glass strip inside the automatic document feeder
1.
Turn off the HP All-in-One, and unplug the power cord.
Note Depending how long the HP All-in-One is unplugged, the date and
time might be erased. You might need to reset the date and time later,
when you plug the power cord back in.
2. Lift the cover of the automatic document feeder.
3. Raise the lid, as if you were loading an original on the glass.
4. Lift the automatic document feeder mechanism.
There is a glass strip under the automatic document feeder.
Chapter 10
92 HP Officejet 6300 All-in-One series
Maintain the
HP All-in-One