I see in many blogs in the internet that cleaning bottles with $\ce{NaOH}$ is very effective. I also realize that industries use caustic soda to clean bottles. Why is caustic soda very effective at cleaning bottles? What makes it so special from other solvents which made it preferable for cleaning?

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    $\begingroup$ Most organic chemistry lab use $\ce{KOH + i-PrOH}$ to clean dirty glassware. $\endgroup$ – Mathew Mahindaratne Apr 2 '18 at 21:14

Caustics such as $\ce{NaOH}$ and $\ce{KOH}$ are effective in converting insoluble fatty acids in organic fats and oils into soluble soaps in a proccess called saponification. The caustics also react with cell membranes, DNA and RNA, destroying undesired yeasts, bacteria and other microorganisms.

That said, caustics react with the glass itself, removing the surface and etching the glass. Use will weaken and damage containers.

Use caution! Caustics also destroy skin and clothing, and are particularly damaging to the eye.

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    $\begingroup$ Did you mean "Caustics such as $\ce{NaOH}$ and $\ce{KOH}$ are effective" instead of "Caustics such as $\ce{NaOH}$ and $\ce{NaOH}$ are effective" ? $\endgroup$ – Avnish Kabaj Apr 3 '18 at 3:31
  • $\begingroup$ @ Avnish Kabaj , Thanks! So much for copy-&-paste. $\endgroup$ – DrMoishe Pippik Apr 4 '18 at 0:02
  • $\begingroup$ Slightly etching the glass is actually a benefit if you really, really want to clean the surface of a vessel. That's why chemists often clean their lab glassware this way. $\endgroup$ – matt_black Apr 4 '18 at 10:25
  • $\begingroup$ @matt_black, true, caustics are effective cleaners. However, getting rid of the last bit of alkali (or sodium silicate that forms) can be a problem for some uses. Also, I've seen caustic reagent destroy glass bottles when left too long. $\endgroup$ – DrMoishe Pippik Apr 4 '18 at 16:23

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