A humidifier is one of those appliances that’s not really on your radar until you need it. Say, when the temperature turns frosty and your skin’s so dry it’s scaly. Or when you—or your kids—come down ...

Luckily, cleaning a humidifier is easy, and you probably already have everything you need to do it at home. To help you through the process, we asked Dr. McKeon and air quality and mold expert Michael ...