Cleaning and caring for a galaxy projector

Before anything touches the glass, blow the dust off. A rubber blower bulb of the sort sold for camera lenses is the right tool and costs very little. Canned air works too, held upright and used in short bursts from a distance.

This step exists because dust is abrasive. Wiping a dusty lens drags grit across the coating and puts fine scratches in it, and scratches are permanent in a way that dust is not. Most lens damage happens during cleaning, not before it.

Once the loose dust is gone, a clean dry microfibre cloth removes what is left. Work from the centre outwards in a spiral rather than back and forth, using almost no pressure — the cloth does the work.

Keep one cloth for optics only and wash it separately without fabric softener. A cloth that has been used on a kitchen surface carries oil, and oil on a lens is much harder to remove than dust.

No glass cleaner, no household spray, no alcohol wipe, no kitchen roll, no shirt sleeve. Optical coatings are thin and solvents lift them; paper products are wood fibre and they scratch.

And never spray anything directly at the unit. If a mark genuinely will not come off dry, put the smallest amount of a proper lens fluid onto the cloth, away from the projector, and use that.

The discs are optics too, and because they are handled every time the scene is changed, they collect fingerprints faster than the lens does. A fingerprint on a disc is projected as a smear across the whole ceiling.

Handle them by the rim rather than the face, and give them the same treatment: blow, then dry microfibre. Keep them in whatever they came in, or in a small box, rather than loose in a drawer where they will rub against each other.

Any device with vents will draw dust through itself, so where it stands matters. A shelf collects less than a floor, and a floor in a carpeted room collects the most of all. If it must live low down, move it up when you are not using it.

Give it air on all sides rather than pushing it against a wall or into a bookcase alcove, and keep it out of direct sunlight during the day — heat and plastic housings are a long-term problem, not an immediate one.

If you are putting it away for a season, or taking it somewhere, the box it came in is the best container you have. Failing that, a bag with the lens facing inwards and something soft against it.

The one thing worth avoiding is storing it somewhere that gets cold and then bringing it straight into a warm room — condensation forms on the inside of the optics and you cannot wipe that off. Let it come up to room temperature before switching it on.