Duh! That was a lapse. I use alcohol. I don't know if it keeps NTM away, but it does handle the other bugs likely to hide in the crevices. Daily 15 min soak in soapy water then rinse and air dry on clean paper towel covered by another. Every 5 days to a week soak 30 min in alcohol after cleaning. I change my neb cup and tubing about every 3 months. I use distilled water if I have it, otherwise bottled spring water. At home I boil water in a tea kettle