We had a Keurig thing with a tank like the one on yours at the office, before the pandemic. I used it to make coffee basically every day, until after a few weeks I realised that the water tank wasn’t gray frosted plastic. It went back to being clear after I (thoroughly) cleaned the whole apparatus 😱 I think I might have been the only person in the office who used that thing…

edit: What I’m trying to say, but forgot to, is that I appreciate your attention to detail that it looked largely the same before and after the cleaning. I sincerely wish we’d had your coffee machine in the office when I started working there.