Charcoal filter can be brushed off with a soft brush or vacuumed. Soaking or using cleaner of any kind is not recommended. Order a new one from the company when it gets too dusty to clean out, when it's bent, when it looks "thinner" or has empty spots, or when you've used it for 2 or 3 years. The carbon helps absorb odors, and gets "used up" after time.
I need the name/model of the machine to tell you what normal/auto means. In any case, daily operation should be in the "normal" setting.