How and when should I clean the projection window?

• Clean the projection window whenever you notice dirt or dust on the surface.
  
  To remove dirt or smears on the window, use a commercially-available cloth for cleaning glasses.
  
  Caution:
  • Do not rub the projection window with harsh materials or subject it to shocks, or you may damage the window.
  • Do not use wax, alcohol, benzene, paint thinner, or other chemical detergents. These can damage the case.