Clean
the projector's obstacle sensor glass (circled in red)
periodically, or if you see a message telling you to remove any
obstacles that are interfering with the projection area.
To remove dust or smudges, gently wipe the
obstacle sensor glass with lens-cleaning paper.
To remove stubborn smudges, moisten a soft,
lint-free cloth with lens cleaner and gently wipe the obstacle
sensor glass.
Warning: Do
not use a lens cleaner that contains flammable gas. The high heat
generated by the projector lamp may cause a fire.
Caution:
Do not use canned air, or the gases may
leave a flammable residue.