Your response just makes me more confident that I'm making the right choice by boiling coffee in a pot of water and washing it with plain dish soap afterwards.
Sometimes when I leave it on too long and it actually boils for a minute or two, there's a coffee ring around the inside of the stainless steel pot. Scrubbing it with a green dish scrub pad gets it off, then soap and water fixes the rest. I never really understood why that ring gets there, but it also gets there from the starch when I boil noodles. I figure it has something to do with electrons on the inside surface of the stainless steel pot losing their ionization or polarization or some sciency stuff. I haven't cared enough to even google it since I know how to fix it and I haven't died yet from it.
You can just buy the commercial cleaner bottle once a year, follow whatever the bottle says and press the "clean routine" button on almost any machine.
There are plenty of machines for which the manufacturer cheaped out on buttons and displays, so instead you press a complicated sequence of buttons that is poorly described in the manual. And a machines, especially drip machines, are not easy to safely rinse, so getting the cleaner back out can be extremely challenging.
I’ve encountered cheap drip machines, and I’ve encountered pricier drip machines. I have never encountered one that didn’t have an utterly terrible path for the water.
And even some rather nice Breville espresso machines have something like three buttons and a couple little LEDs. They work well, but good luck deciding the blink pattern meaning “you must descale me now” and actually running the descaling cycle without a manual.
I was always particularly concerned about that tube where the heated water goes from the bottom to the top and pours into the coffee filter. It's so thin, I could never believe it could be cleaned from whatever buildup is inside it.
