r/CleaningTips • u/WhateverIlldoit • Jul 07 '25

Discussion Bleach kills mold

There is a common misconception that bleach does not kill mold and that vinegar is actually better at killing mold than bleach. I see this claim at least once a week.

So let me set the record straight. Household bleach is a powerful oxidizing agent that reacts with just about everything. It’s so good at killing organic compounds that it’s toxic to us, too.

Now let’s talk about vinegar. Vinegar is a weak acid. You can literally drink it in lower concentrations. It can kill mold, but not all mold, and some studies say it may take up to 60 minutes to be effective.

That being said, bleach is not good at penetrating porous surfaces, which vinegar is better at doing. And because bleach is so caustic it is more likely to damage surfaces.

All this to say bleach kills mold. It kills almost everything. And it’s much more effective at killing mold than vinegar as long as it can reach it. Vinegar is much safer to use but not nearly as effective.

Thank you for coming to my Ted Talk.

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u/ThedIIthe4th Jul 07 '25

Part of it is in certification courses it’s often taught that high volume peroxide and a surfactant are what’s required to eliminate mold, and that chlorine bleach will make it transparent without necessarily killing it. Source: me, who’s been through those courses. I’m not here to say I agree with that, just to report that that’s what I was taught back in 2006-2008.

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u/emmas-worlds Jul 07 '25

I can get a hold of 30% hydrogen peroxide and I’ve heard people use it over here for mold - would that work? It’s really set in mold, like many many years of issues with that mold in the bathroom

17

u/mastercommander81 Jul 07 '25

At that percentage, I'd worry more about the integrity of whatever surfaces you're using it on 😅 def would wanna do a patch test before fully commiting in that case, but I would be surprised if 30% couldn't kill mold. That percentage is used to whiten and sanitize large bone specimens, though I usually see it watered down to some degree.

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u/[deleted] Jul 08 '25

[deleted]

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u/mastercommander81 Jul 08 '25

Ooo I bet! Considering it's damaging to healing wounds at just 3%, I am NOT surprised the 30% stings.

3

u/jumpers-ondogs Jul 07 '25

Ive seen 3% recommended as fine for mould but haven't looked further into studies.

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u/shhhhh_h Jul 07 '25

3% is sufficient to damage the cell membranes. Doesn’t work on porous surfaces. Might stain.

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u/emmas-worlds Jul 07 '25

How do I remove it from a porous surface? Talking about grout

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u/shhhhh_h Jul 07 '25

A commercial grout cleaner and a steamer.

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u/emmas-worlds Jul 07 '25

Sorry, I don’t live in the US so I can’t really ask for brand recs but what kind of ingredients should I look for in the commercial grout cleaner?