We understand the importance of knowing that your toothbrush is sanitary, and we are disappointed to hear that you have experienced mold on your Oral-B iO 2 Toothbrush. All of our products go through rigorous research and consumer testing in the hopes of bringing you a product you will love, and please know that your feedback is being shared with our Quality Team. It sounds like you do a great job of cleaning your brush every day, and this is not something that we would expect. For a deeper cleaning, we recommend soaking the adapter portion of the brush in warm water overnight, scrubbing with a soft-bristle brush, and then holding the adapter under warm water while it is running, before drying the brush off. We would love a chance to learn more about your experience so we are better able to assist you, and we encourage you to give our team a call at (800) 566-7252.