Microtek 9800XL - cleaning

A few questions about the cleaning of a Microtek 9800XL A3 flatbed scanner. How to reach the CCD in order to clean the haze which has most likely accumulated on the glass covering the sensor? The top cover with the glass is easily unscrewed and lifted. But does the scanning head lift from the rails or should it be slid out to the front? If latter, can't see how to do it without removing part of the metal frame. Has anyone successfully cleaned the CCD on this particular scanner? Thanks for your answers.

Anyone?