sodium hydroxide old

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Melinda Novak

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I found an old box of sodium hydroxide in my garage and some of it leaked out. looks dry. would you assume it's not fit to use for soap making now? thanks for any advice.
 

DeeAnna

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Do NOT mix dry NaOH with vinegar, for safety's sake. Yes, I know theoretically you can do that, but what is possible in theory and what is best in actual practice are two different deals.

If you must dispose of dry NaOH and it's more than a few ounces, take it to your local hazardous waste disposal site so they can dispose of it properly. Many towns and counties in the US offer this type of program.

Do NOT dispose of NaOH in your regular trash -- it could cause a horrific accident.

If you only have a little bit -- a few ounces -- then make a lye solution exactly like you were making soap -- pour the NaOH into water, mix until it dissolves. Use 4 or more parts water to 1 part NaOH by weight. Then pour the solution slowly down the drain with lots of cold water from the faucet.

Or keep the NaOH and use it in your drains to clean them just like you would use normal drain cleaner.
 

Backdraft

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Gee, I guess I’ve been doing it wrong for my entire 35 years as a FF/EMT, huh?
 

cmzaha

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Gee, I guess I’ve been doing it wrong for my entire 35 years as a FF/EMT, huh?
DeeAnna always take the safest approach for the average person. You obviously know what strength vinegar to use and how much lye at a time to not cause an accident, but many would not know, and you would know how to handle an accident, (volcano) if it happened, the average person would not.
 

DeeAnna

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"...Gee, I guess I’ve been doing wrong for my entire 35 years as a FF/EMT, huh?..."

You do what works for you. We also have people who pour water into dry NaOH and think nothing of it. And we've had people who absolutely insist on using vinegar to neutralize NaOH on the body.

The fact that these methods apparently work fine for some people doesn't mean they're normal and acceptable chemical procedure to be used by everyone. We have a lot of newbies reading this forum who don't have any chemistry training, and I will not advise them to use anything other than the safest methods possible.
 

Backdraft

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DeeAnna always take the safest approach for the average person. You obviously know what strength vinegar to use and how much lye at a time to not cause an accident, but many would not know, and you would know how to handle an accident, (volcano) if it happened, the average person would not.
Like poring powdered Lye down the drain “like normal drain cleaner”? Talk about a perfect opportunity for a ’volcano’! Ok. Well, sorry I weighed in. Have a good day all.
 

DeeAnna

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I said to use the NaOH "just like you would use normal drain cleaner." Using NaOH in a recommended way as a drain cleaner is not remotely the same thing as "just pouring powdered lye down the drain."
 

BlueIris

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My first husband was a plumber and used NaOH to clean drains. He knew what type of systems to use it on, septic system verses public sewer, what types of trap systems, grease traps, residential et. Way more than I will ever know. Therefore I do not use lye in my drain system. But I have disposed of a bad batch of lye heavy soap using the vinegar system, wrapped in cat litter and brought to my local dump. I kept it around til it tested neutral first, then took it in. Additionally, I use old lye for soap. Never had a bad batch out of it. Probably not very old lye, but who knows, could work.
 

DeeAnna

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Good point to use the old NaOH to make soap if it seems at all reasonable to do so. It's always better to use materials than discard them, especially hazardous chemicals like NaOH. I once had a carton of NaOH split open. I safely discarded the hard lumps that had formed near the opening and used the rest in soap.

If a person wasn't confident about the purity of the lye, it might be reasonable to choose a 0%-2% superfat. That seems awfully low to many people, but bear in mind that soap recipe calcs are based on the assumption that the NaOH is 100% pure. The NaOH we use is typically closer to 95%, give or take a few percent, so this assumption builds in some "hidden" superfat. The true superfat will be higher than the superfat number you type in.
 

cmzaha

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I would also use it for making soap, doing as DeeAnna mentions to discard by diluting down the clumps and disposing them down the drain. When I do that I dilute the lye in a large amount of water
 

madison

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I do the same practice, my dad taught me that when I was younger, he is not a plumber though.
 

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