The mask is not meant to be placed into the washing machine. Simply use a damp cloth with a drop of soap and rub the out layers. Rinse the soap off your cloth then wipe it again and lay it up to dry. Do note that washing the mask doesn't clean the filter media as this is in between the outer layers. The valve can itself be cleaned with the same method but don't take the valve out as it is meant to be permanently attached to the mask.
It all depends in what kind of environment you live in and how often you use it. The typical shelf life Kandymask is around 6 months. Once you notice it becoming harder to breathe through the material it is usually the time to replace it.
The dual valve system opens when you breathe out and closes when you breathe. The valve automatically closes during inhalation to prevent harmful airborne contaminants from entering your lungs. It also allows for the exit of moisture on hot sweaty days.