I do not trust just using the baby bottle sterilizer on its own. I think Dr Falkinham suggested always boiling for 10 minutes minimum and then 1 minute for each 1000 feet of elevation. I have been doing this and THEN using the Grownsy baby bottle sterilizer with NO water in it and it turns on and dries for 70 minutes with a 15 minute UV treatment after that. Dr F also says UV alone does not do it so I do all this every single time I use any neb cups, including for Cayston.