I was lots more successful with humidified air. If you have a raw throat, or if you have a stuffed up nose, humidity will take care of it. Another way to help is to drink enough fluids.

Note that I turned down the default temperature and humidity.

As to the cleaning - you need to clean it anyway. Your exhalations do go down the tube backwards. When I first started using it I would get tired of cleaning and put it off and got a really bad head cold.