My humidifier has a Brown Residue in it, what is that?

This is called Limescale, which is a buildup of minerals contained within your water. To rid your humidifier of this, we're recommending mixing 3 tablespoons of white vinegar per 1-gallon of water. Use a sponge, or brush (if included) with the solution and wipe and rinse thoroughly. 

This is not caused by your humidifier, but rather the minerals in the water used to run your humidifier. We recommend using Distilled water to prevent this from happening.