Cloudy glass and a weak mist are not dirt. They are oxidized oil resin. Here is the two-minute high-proof alcohol flush that restores full output.

Faint, flat mist? It is usually not the oil. A thin oxidized film coats the glass airway. Skip soap and water; a two-minute alcohol run clears it.

Thick base notes like sandalwood and vetiver are too viscous to climb a nebulizer tube alone. The fix: blend 1 part base note to 3 parts a light top note.

When your diffuser’s scent seems to fade, it isn’t the oil. It’s olfactory adaptation, and three small habits bring the aroma back.

A reader asks how long is too long. The short answer is rooted in olfactory adaptation: diffuse 30 minutes, pause 30 minutes, and a little less is almost always a little more.

A reader asks: do essential oils expire? Yes, but the timeline depends on chemistry. Citrus 6-12 months, florals 2-3 years, woods and resins often improve with age.