Five minutes a week. Years of evenings.

Clean whenever you switch oils. A quick alcohol rinse between Citrus Glow and Winter Pine keeps each blend tasting of itself rather than of what came before.

Never put water or vinegar in the glass. The Walnut & Glass Nebulizer runs without water. Water will not atomize and sits in the jet, and neither water nor vinegar dissolves essential oil, so residue builds up where you cannot see it. Alcohol is the cleaner that works on oil without harming the delicate glass micro-tubes.

Use thin, pure oils. Essential oils and diffuser blends without carrier oil run clean. Thick oils such as vetiver, sandalwood or resins, and anything cut with a carrier oil, will clog the jet; blend them with a lighter oil if you want to use them.

Do not overfill. Twenty to thirty drops is plenty. The oil level should stay below the top of the inner tube so the air has room to work.

Keep the output moderate. Higher output empties the glass faster and can leave a fine film around the mouth. The two-on, one-off cycle is designed to keep a room scented at a low setting.

Fresh water every time. Fill the reservoir to the line with room-temperature tap water (200 ml in the Dome and the Bell, 120 ml in the Lantern), then add your blend on top: five to eight drops, or three to five in the Lantern. Filtered or distilled water leaves less scale on the plate, so the weekly clean stays quick.

Do not overfill. Water above the line reaches the opening in the dome and the mist turns to spitting. Below the minimum all three switch themselves off, which is normal.

Pure oils only, in the water. Essential oils and diffuser blends without carrier oil mist cleanly. Carrier oils, thick resins and anything perfumed with alcohol coat the plate and dull the mist.

Empty it when it is done. Standing water goes stale and the oil film hardens. If you will not use it for a day or two, pour it out and leave the dome off so the bowl dries.

Use the timer on the Dome. One, three or six hours covers an evening or a night; continuous is for a large room with the door open. The Bell and the Lantern have no timer; they simply run until the water is gone, then stop.

Three of the bases are solid wood, walnut on the Nebulizer, oak on the Dome and beech on the Bell; the Lantern's is white and wipes clean. All of them want the same thing: a dry or barely damp cloth, and nothing more. Never submerge a base, rinse it under a tap or let liquid pool on it; the pump or the electronics live inside the block, and water can ruin them and warp the wood. Keep harsh chemicals, solvents and polishes off the surface too; they strip the finish. If a drop of oil lands on the wood, lift it straight away with a dry cloth. When you empty the Dome, the Bell or the Lantern, pour from the side away from the controls so water does not run over the base.

The Nebulizer's filament lamp is decorative and runs warm, not hot. Let it cool before handling, and dust it with a dry cloth rather than a wet one. If it ever needs replacing, write to us and we will point you to the right bulb. The Dome's flame-coloured light, the Bell's glow and the Lantern's are sealed under the reservoir and need no care beyond keeping water off the base.

Keep all of them away from direct sunlight and heat sources, and store essential oils capped, upright and out of the light. Oils keep their character longest in a cool cupboard.

Nebulizer: weak or no mist. Almost always residue in the jet. Do the alcohol rinse, run it a little longer than usual, and make sure the glass is seated firmly on its mount.

Nebulizer: oil pooling at the mouth. The output is too high for the oil you are using, or the glass is overfilled. Lower the setting and wipe the rim.

Nebulizer: louder than usual. Check that the base is on a flat, solid surface and that the glass is seated; a loose glass hums.

Dome, Bell or Lantern: light on but little or no mist. The plate needs the vinegar clean, or the water is below the line. Clean, refill with fresh water and try again.

Dome, Bell or Lantern: spitting or water around the base. Overfilled, or the unit was moved while full. Pour a little out and keep it level on a flat surface.

Dome, Bell or Lantern: switches itself off. That is the dry-run protection: the water has run out, or on the Dome the timer has finished. Refill and restart.

Anything else, write to us and include a short description of what you see. Most issues are solved in one reply.