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I was making soap using a guide for the first time. I accidentally used an aluminium container. It has lye and olive oil in it and was kept on the stove; now it is bubbling and not ceasing (I've turned off the gas).

What should I do to stop it?

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    $\begingroup$ Buy another container, I guess. $\endgroup$ – Ivan Neretin Jul 4 '17 at 15:36
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    $\begingroup$ Tyler Durden used a stainless steel pot, I believe. Also, look for the liposuction clinic if you want to improve your product. $\endgroup$ – andselisk Jul 4 '17 at 15:58
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    $\begingroup$ @andselisk I couldn't help but upvote :D $\endgroup$ – Mithoron Jul 4 '17 at 17:19
  • $\begingroup$ Fill it into an empty plastic can. I wouldn't pour it down the drain, lest it solidifies in your gutter. Probably won't happen with olive oil, but it's your bet. $\endgroup$ – Karl Jul 4 '17 at 22:04
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Slowly add vinegar. DO NOT TURN THE FLAME BACK ON.

Most likely, the alkali concentration is high enough that you've dissolved away the passivating oxide on the aluminum, and the exposed aluminum metal is reacting with water to form $\ce{Al(OH)4-}$ and hydrogen gas. Adding vinegar should bring the $\mathrm{pH}$ back down into a range where the aluminum can passivate again, stopping the reaction.

The batch of soap is probably already ruined, so I wouldn't worry about that.

In the future, I would recommend using a cast iron or mild steel (not stainless) pan for this procedure. Plain iron is remarkable for its resistance to alkali, in my experience.

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    $\begingroup$ Since the batch of soap is lost anyway, we may just as well empty out the container and wash it. Chances are it is already damaged too badly, though. $\endgroup$ – Ivan Neretin Jul 4 '17 at 15:39

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