Use a fluid that states it is free of alcohol and ammonia, spray it onto the cloth and never onto the screen, and use a microfibre cloth rather than anything coarser.
The order for a screen
- Switch off and let it cool — a warm surface dries the fluid into streaks.
- Dry microfibre first, lightly, to lift loose dust. Dragging grit across a coating is what scratches it.
- Damp cloth, sprayed away from the screen, in straight overlapping passes.
- Dry side of the cloth to finish.
Why spraying the screen is the risk
Fluid runs down the bezel and into the electronics at the bottom edge. That is the failure this shelf actually causes, and it is entirely avoidable.
The order for a projector lens
Blow first. A rubber blower removes dust without touching the glass, and dust is abrasive. Only then a lens cloth or a lens pen, in a spiral from the centre outward. A lens is a smaller, more curved and more delicate surface than a screen, and it deserves the extra step.
The filter
If the projector has one, the manual states the cleaning interval in hours. A blocked filter raises the internal temperature, which shortens lamp life and makes the fan louder — two symptoms people attribute to age.
Questions people actually ask
Why not use glass cleaner?
Household glass cleaners typically contain ammonia or alcohol, and modern panels and lenses carry anti-reflective coatings a few microns thick that both dissolve. The damage is permanent, gradual, and looks like haze rather than like a mark.
What about the dust inside a projector?
Filters are user-serviceable on machines that have them, and the manual states the interval. Anything beyond the filter — the optical block, the panels — is not, and opening a projector to clean it is how dust ends up somewhere it cannot be removed from.
Last reviewed 4 September 2026