I dug deep on the Internet the other day and found a number of studies showing that the best method is baby bottle sterilizers. With some of them (e.g. Phillips Avent), you can just leave the lid on with the sterilized stuff in it for up to 24 hours until you use it again. (Cheaper, though, is getting a microwave bottle sterilizer some of those can also be left with the lid on until next use, like this one).