I think moisture gets into it just using it. I know mine is very dry when I start out. First I use it sitting up. Then before using it laying down (back, left, right) I tap it onto a paper towel. You can see the moisture drops. This way it does not fail or if it does I just give it a shake or tap again. By the way I think you are the one that posted about your Dr telling you to use the Aerobika laying down in different positions. That advice has been critical for me as most of my mucus will NOT come up until I lay on my back head slightly inverted and pillow under my hips using the Aerobika. So THANK YOU for posting about that some time ago. It was a huge help for me just at the right time.