How to properly clean a whiskey flask?

Question

I found an old stainess steel flask that someone once gave me. I want to use it again to hold whiskey.

There doesn't seem to be any liquid inside, though it may have contained some just before the flask was forgotten.

A stainless steel flask

How do I properly clean to start using it again? Just hot water? No soap? Can I trust it? It was only used to hold whiskey.

score 8 · Accepted Answer · edited Dec 21 '12 at 16:53

I'm answering my own question because I did a bunch of stuff from a lot of resources, and collected valuable information that more people may use in the future when coming across this post.

I wanted to use household items. My flask is a stainless steel with some copper.

What I actually did:

Cleaned with a small amount of tap water, shaking it a little bit;
Boiled a glass of water, and a bottle of vinegar/water (50%/50%);
Cleaned the flask with the boiled water, them with the vinegar solution (50% of the flask, shaking it a little bit). Then cleaned again with the boiled water (50% of the flask), shaking it, them with the vinegar solution again, then with the boiled water (50%), then with boiled water again (this time 100%). I didn't emptied the flask from this last cleaning;
I let the water inside for 24h;
24h later, I opened the flask, and emptied it in a glass cup: there wasn't any solid particles, and the water didn't have any taste, so I believed it was ok to put some whiskey.

Maybe your flask is an old one, with leather, I don't know. In this case, I suggest you check these resources:

http://www.whiskywhiskywhisky.com/forum/viewtopic.php?f=16&t=4254

http://www.thetfp.com/tfp/tilted-knowledge-how/29045-cleaning-inside-antique-hip-flask.html

http://ask.metafilter.com/111820/Mildewsmelling-hip-flask-can-it-be-salvaged

http://forums.overclockers.co.uk/showthread.php?t=18080329

lol I agree with Carey - though funny as it is, the easiest way to clean it might have been to just put whisky in it and leave it over night. — Kai Qing, Aug 28 '15 at 22:35

score 6 · Answer 2 · edited Dec 20 '12 at 23:14

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If there's no evil smell emanating from the flask, just give it a good rinse with hot water. Otherwise, a 20 minutes soak in a dilute solution of bleach (around 1 tbs per gallon), followed by extensive rinsing with warm water should do the trick.

edited Dec 20 '12 at 23:14

samthebrand

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answered Nov 05 '12 at 03:43

score 5 · Answer 3 · answered Nov 05 '12 at 14:50

Is the flask actually stainless, or merely something that's been plated bright and shiny? I'd go w vigorously shaking some sand around inside of it, to loosen any corrosion/crud deposits. Follow that w hot water/detergent, and brushing as possible. Finally, give it a soak in Vodka/Everclear. Check to see that the rinse solvent comes out clear and without chunks. For all you know, someone from the 1990's left Cream liqueur in there to evaporate.

score 5 · Answer 4 · answered Nov 06 '12 at 12:39

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Steradent tablets are best for cleaning any type of flask in my experience.

answered Nov 06 '12 at 12:39

Echilon

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score 3 · Answer 5 · edited Dec 20 '12 at 21:14

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There are a number of flask and bottle brushes available online that will help with this task. I also found this set of instructions at ehow that recommends the use of boiling water and distilled white vinegar. Unlike most cleaning products, white vinegar will not leave a lingering scent in the flask.

edited Dec 20 '12 at 21:14

samthebrand

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answered Nov 05 '12 at 18:49

Kristina Lopez

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Note that ehow content often seems to be written by people who are not exactly experts; in this case I'd say sure, vinegar is generally great for cleaning, but the specific instructions are likely only one of many ways that'd work. – Cascabel Nov 06 '12 at 15:33
@jefromi, which is why I vet my sources and use judgement before passing anything along to our community. Thanks for your input! :-) – Kristina Lopez Nov 06 '12 at 16:12
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Sure, I'm just saying - in this case, I think the important thing is the use of vinegar, not the specific instructions. (I suspect for example that you could stir with something other than a spoon, and more seriously, that a funnel would be a good idea, and that heating the vinegar would help at least as much as heating the water.) – Cascabel Nov 06 '12 at 17:40
I agree - and that a brush would do an even better job if one is available. The funnel is definitely a good idea. – Kristina Lopez Nov 06 '12 at 19:01

score 3 · Answer 6 · answered Dec 22 '12 at 14:27

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I have always had a lot of success using uncooked rice as an abrasive and a dish soap/hot water combo. Shake it like crazy and it's clean. It's a safe, simple, and effective method.

answered Dec 22 '12 at 14:27

Jason

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score 1 · Answer 7 · edited Aug 28 '15 at 17:40

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Great question and some really good answers.

I am the founder/craftsman of a company that sells flasks and we recently wrote a blog post on it that can be found here: http://1776.co/blogs/journal/54690755-how-to-clean-your-leather-whiskey-flask

The short of it is:

Use warm soapy water and allow it to air-dry. Your flask should always be washed by hand because the chemicals in dish washing detergent may react with the stainless steel interior.

edited Aug 28 '15 at 17:40

Jay

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answered Aug 26 '15 at 21:26

Isaiah Jones

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Actually, the advice you give further down on the page under 'If you have not used your flask for a while' might be more applicable in this case, rather than the cleaning it for first use. – Joe Aug 28 '15 at 17:47

How to properly clean a whiskey flask?

7 Answers7