You mean barely coffee water? Always at a hotel I'd make like four cups of water just to clean some of it out and even then it was still lingering. Ew. I should have brought a cleaning brush and bleach.

I now have a two cup collapsible electric kettle, for travel. (Got the company to reimburse me for it after I pointed out that tea should not taste like coffee water.) Because I refuse to put barely coffee water in my tea, thanks.