Don't know why, but these cleaner packets really, really work. My husband loves his new Breville tea maker but isn't terribly fastidious about keeping it clean. As the stains began to increase, he finally tried one of these packets, following directions, and was completely blown away by how easy and successful the cleaning process was. Said the tea tasted as good afterwards as it had when the machine was brand new. He now uses them weekly and routinely reminds me to buy more of them for him. He's been known to recycle the cleaning fluid after use in his Breville by pouring it into clean but stained tea mugs, even an electric egg boiler with scale accumulating on it. Presto! His tea mugs now look fresh and unstained, and his egg boiler is working smoothly again. Short of a magic wand, I don't ever expect to find anything else as inexplicably but simply effective as these little packets. Expensive, people say? Worth absolutely every penny, I say.P.S. If you're a tea fanatic and haven't tried the Breville yet, you've got a treat coming to you. My husband refused for 3 years to let me buy him one and only gave in with very poor grace a few months ago. It's now the favorite thing in his life (after me, of course!). Perfect tea, again and again, without having to wait or to keep track of time? Having it stay hot once it's ready, in case he got distracted and doesn't get back to it for a little while? He's totally thrilled, even after claiming furiously that he'd been making tea for decades and didn't need a multi-hundred-dollar machine to do it for him. Guess what? It's a luxury to be able to do something else while it's in the works and not to have to worry about it coming out right. He uses it three or four times a day. A huge win!