I have a Visoneer 9020 that has developed an oily film on the underside of the scanning glass. It now affects my color scans with a white background...I get a pink background in the scan. In attempting to take the unit apart to gain access to the underside of the scanning glass I seem to have run out of options. I have removed all the screws on the bottom of the unit and have still not been able to separate the bottom and top halves without making a conscious effort to break the plastic case. Has anyone run into this problem? Any ideas? Bill