The manual says:
For instructions on cleaning the underside of the scanner glass, go to
www.hp.com/support, select your country or region, navigate to the
support page for your scanner, then click the link to view information
about cleaning the underside of the glass.
So they at least promise to supply the information, and a support
request might be honored.
Here's info from a different HP scanner:
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If the 6200C is like the 6100C, which is mechanically similar
to my 4C ...
0. Disconnect power. Take anti-static precautions.
1. Remove the auto-feed assembly.
This should expose the rear Torx screwheads.
2. Remove the metal covers over the 2 front Torx screw heads.
3. Remove the screws and lift off the upper case w/glass.
4. Clean and replace.
Search the net for further platen glass cleaning advice.
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Regards, Bob Niland private.php?do=newpm&u=
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Best regards,
Spehro Pefhany