# How can I clean the coffee stains from the bottom of my thermos? **URL:** \ **Category:** Factual Questions\ **Created:** [December 30, 2000, 5:51pm UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806 "2000-12-30T17:51:23Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![Murphy](https://avatars.discourse-cdn.com/v4/letter/m/5fc32e/32.png) [@Murphy](https://boards.straightdope.com/u/Murphy)\ **Post date:** [December 31, 2000, 7:47pm UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806/21 "2000-12-31T19:47:19Z")
I’ve always put my thermos on the bottom shelf of my dishwasher. The cork and cup won’t hold up too well but then they can be hand washed. ---
**Author:** ![Tzel](https://avatars.discourse-cdn.com/v4/letter/t/f4b2a3/32.png) [@Tzel](https://boards.straightdope.com/u/Tzel)\ **Post date:** [January 1, 2001, 6:04am UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806/22 "2001-01-01T06:04:13Z")
I will second the “don’t clean it” sentiment. While it may not look nice, it will make the coffee taste better. Plus, if you get a good enough layer, anything you put in there will come out as coffee! Jonesin’ for a fix of caffeine? Just pour in some hot water, wait a little while, and like magic, coffee! I know people that have bragged about not having washed their coffee cups for years. ---
**Author:** ![Tzel](https://avatars.discourse-cdn.com/v4/letter/t/f4b2a3/32.png) [@Tzel](https://boards.straightdope.com/u/Tzel)\ **Post date:** [January 1, 2001, 6:05am UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806/23 "2001-01-01T06:05:16Z")
Oh yeah, and welcome to the SDMB, Murphy. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [January 1, 2001, 6:15am UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806/24 "2001-01-01T06:15:21Z")
> [@](#): > > \*Originally posted by Tzel \* > \*\*Oh yeah, and welcome to the SDMB, Murphy. \*\* And **Murphy** , if **Tzel** offers you a cup of joe with that gracious welcome, it’s ok to politely decline. 😃 Peace, mangeorge ---
**Author:** ![Murphy](https://avatars.discourse-cdn.com/v4/letter/m/5fc32e/32.png) [@Murphy](https://boards.straightdope.com/u/Murphy)\ **Post date:** [January 1, 2001, 6:52pm UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806/25 "2001-01-01T18:52:44Z")
Thank-you Tzel for the welcome and thank-you Mangeorge for the advice. Here’s wishing you both a happy new year and many cups of fresh brewed Columbian java. ---
**Author:** ![Tiburon](https://avatars.discourse-cdn.com/v4/letter/t/e36b37/32.png) [@Tiburon](https://boards.straightdope.com/u/Tiburon)\ **Post date:** [January 2, 2001, 1:22am UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806/26 "2001-01-02T01:22:48Z")
Well, haven’t tried the alka seltzer because I just don’t have any on hand. I’ve heard the different suggestions that involve rice, ice, lemon juice, all those good things. I think they work only moderately well on the stainless steel. More of a glass coffee pot cleaner, if I remember correctly. I will try that CLR stuff and let you all know how it works. As for drinking coffee out of the thermos, period - well, I work in an office where the coffee looks like water dressed in brown. It’s weak and out of a can. Instead, I grind up some beans, make myself some coffee, have one cup and take the remaining 2 cups to work with me in the thermos (it’s the perfect size!). It isn’t fresh from the pot but it isn’t so weak that I could fall asleep just looking at it. 🙂 Tibs ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [January 2, 2001, 2:57am UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806/27 "2001-01-02T02:57:10Z")
Tiburon, why don’t you do what I do? I have a small coffee brewer at work, and a small grinder, and a small canister. I grind my coffee and brew my own 4-cup carafe of coffee, fresh, piping hot, and a nice aroma. Aaaaahh! ---
**Author:** ![Yeah](https://avatars.discourse-cdn.com/v4/letter/y/dbc845/32.png) [@Yeah](https://boards.straightdope.com/u/Yeah)\ **Post date:** [November 17, 2001, 4:41am UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806/28 "2001-11-17T04:41:52Z")
For 20 years I got brown stains in my coffee thermos…but NO MORE! I started filtering my tap water through one of those pitchers with a filter cartridge in it and now the bottom of my thermos is perpetually bright and shiny. Not only that, but when I started using filtered water the stain that was already in the thermos disappeared. I’m serious. If some chemist or food scientist can explain to me (1) what the brown stain is made of, and (2) why it doesn’t accumulate when I use filtered water, I would appreciate it. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [November 17, 2001, 5:08am UTC](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806/29 "2001-11-17T05:08:18Z")
I have absolutely no idea, **Yeah** , but I really like my [manual coffee grinder](http://boards.straightdope.com/sdmb/showthread.php?threadid=60515) It works great. Thanks, all. 🙂 Peace, mangeorge [Previous page](https://boards.straightdope.com/t/how-can-i-clean-the-coffee-stains-from-the-bottom-of-my-thermos/47806.md?page=1)