How can i prevent my sinuses cavities from getting dry?

Humidifier: Humidity can help moisten them as well as some inhalant meds otc.

Humidity: In the winter a humidifier works well. Some otc sinus inhalers or mists work well too.

Different ways: A number of ways to do this. Some of the simple ones: a neti pot will help keep passages clean (which will help keep them balanced and moist), saline nose spray. I've personally used a Bacitracin ointment (a small dab just inside the nose)-it seems to help. Removing (if you can) the cause of dryness will definitely help.A forced air system is drying, try using a humidifier (but keep very clean).