Dissolve the white crust in a humidifier with citric acid
#0067 Home & daily life
Fact rank
A
A humidifier maker's care instructions (primary) confirm that citric-acid soaking is specified for the white crust, and that it is calcium and other impurities from tap water
Wow rank
B
Citric acid for limescale is a well-known cleaning staple
Usefulness
S
Directly useful for a seasonal appliance that needs regular care
Verification: Supported by evidence
AI verification reports the evidence it found; it does not guarantee that a claim is true.
The hard white crust that builds up on a humidifier's tray and filter can be removed by soaking them in water with citric acid dissolved in it.
Why
The white deposit is minerals such as calcium and magnesium dissolved in tap water, left behind and built up as the water evaporates (limescale). Surfactants barely touch it; it needs to be dissolved with acid.Evidence
Primary Sharp, humidifier filter care. Dissolve about 6 g of citric acid per litre of water or lukewarm water (about 40°C or below), soak for about 2 hours and rinse thoroughly. The white or reddish-brown deposits on the filter are impurities from tap water (such as calcium) and are not a fault link
Primary Sharp call-centre advice (humidifying air purifier filter and tray). Soak in citric acid solution for 2 hours to remove the white crust, rinse, then soak in baking soda solution for odours. Do not mix citric acid and baking soda: it foams and loses its cleaning and deodorising effect link
Secondary Panasonic lifestyle site, explanation by cleaning expert Chiaki Fujiwara. Limescale is built-up minerals from tap water such as calcium carbonate and magnesium carbonate, and feels gritty. Hardened scale can hardly be removed with surfactants and must be dissolved with acid link
Notes and limits
Amounts and times vary by model, so follow the instruction manual. Slime and odours are a different kind of dirt; Sharp's humidifying air purifiers use baking soda for them, but never at the same time as citric acid. Do not mix chlorine-based cleaners with citric acid (#0034). The white scale on bathroom mirrors comes from the same tap-water minerals (#0030).
Derivations
Derived from: 汚れと洗剤は相性で選ぶ
Derived facts: —