text: what can i clean the filter of my cool mist humidifier with.i cant afford a new filter right now? something that wont be harsh if dispersed in air. i have asthma.thanks a lot! most humidifiers of that type have filters that are made of cardboard or paper, and are very difficult to clean without destroying them.  if you're one of the lucky ones with a metal or cloth filter, you can clean it somewhat by soaking it in vinegar for an hour or two.