How do I clean the scanner glass on the HP ScanJet Pro 2500 F1?

Lift up the document feeder, then use a clean lint-free cloth moistened with water or glass cleaner to thoroughly clean the flatbed scanner glass. Do not spray glass cleaner directly on the scanner glass as this might cause permanent damage. Dry the scanner glass completely with a dry, soft, lint-free cloth before turning the scanner back on. (Page 27)