Let's say I have a cup full of milk that had been at room temperature for months (apparently my son was running an experiment...). The smell started seeping out of the makeshift lid, and it's horrible. I have no background in chemistry but I imagine there might be a way to neutralize the smell before getting rid of the contents.

I'm worried if I just flush it down the pipes it might linger and make the whole house smell. Also, ideally I would like to salvage the cup because it's a very nice handmade glassware (he was running a fancy experiment).

Again, this has been there for months so I hope there isn't any dangerous bacteria still around, and any advice to get rid of the smell and clean the thing would be enormously appreciated.

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    $\begingroup$ Ew just flush it already. Nothing's going to happen. And about the glassware just wash it many times with hot water and a good dish soap. If you can't take the smell while disposing it spray perfume or something while covering your nose. Hopefully there's nothing nasty growing in it which BioSE could be aware of. There is bacteria in it for sure but don't worry you won't turn into a StanLee character. Moreover, avoid direct skin contact. The smell could stay on skin plus the bacteria are unpredictable. $\endgroup$
    – Desai
    Commented Apr 19, 2021 at 21:19
  • $\begingroup$ That was a nice spook on the profile @Desai :) And lol "nothing nasty in it which biose could be aware of" $\endgroup$ Commented Apr 23, 2021 at 19:35
  • $\begingroup$ @Buraian You mean the "I know who you are?" $\endgroup$
    – Desai
    Commented Apr 23, 2021 at 22:47
  • $\begingroup$ I was the culprit who upvoted this question because I thought it was funny and I wanted more members to read it which becomes a high possibility when upvoted. Little did I know... $\endgroup$
    – Desai
    Commented Apr 23, 2021 at 22:51

1 Answer 1


The disgusting smell is probably butyric acid. Try adding a base: For example, washing soda (sodium carbonate), or perhaps drain cleaner (sodium hydroxide, be careful with this one, this is very corrosive to people/eyes), or even ammonia. This should turn the butyric acid into butyrate ion, which should be much less disagreeable. Then flush down the drain.

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    $\begingroup$ Even baking soda (sodium bicarbonate) will work, though washing soda is better. $\endgroup$
    – Andrew
    Commented Apr 19, 2021 at 22:54
  • 1
    $\begingroup$ I would be careful not to mix cleaners, e.g. ammonia and bleach. Just in case: doh.wa.gov/youandyourfamily/healthyhome/contaminants/… $\endgroup$
    – Buck Thorn
    Commented Apr 20, 2021 at 13:20

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