Just soak the plastic parts in a solution of hot water and dawn dish soap. Then after 15 -30 min soak just rinse and let dry. . If she is not sick that should be sufficient. Sometimes you can add vinegar to the water as an antiseptic. Don't make the procedure too hard. After nebulizing have her put them in a bowl of the dawn and hot water. It can sit all day if she is tired to rinse them off.