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Borax (wikipedia.org)
81 points by js2 42 days ago | hide | past | favorite | 47 comments

One of the really day-to-day useful uses of Boric Acid (I believe borax is also effective) is to add it in powdered form to shoes to kill any bacteria growth.

I started doing this a few years ago after watching a video from Big Clive where he mentioned it, and it has really made a difference. No more smelly shoes, socks or feet and no fungal growth.

Seems silly but living under the tropics and macerating in closed shoes all day does have these rather annoying side effects, and whatever shoes you wear, sweat and a warm environment are a breeding ground for bacteria.

Adding about half a teaspoon of powdered boric acid to each shoe at least a couple times a week makes a huge difference.

Best is in new shoes, they will smell like new even a couple of years later. I'm not even exaggerating when I say that at the end of a long day, socks only smell of fabric softener and feet smell of well, nothing.

Another solution is the spray them with isopropyl alcohol. I do this with sandals if they ever start to smell. Works great. Smells for a bit while it evaporates but then it is fine.

Boric acid still makes nervous but it is completely safe?

Boric acid is very inert. It tastes like chalk. The Wikipedia page says there are some some/weak evidence that it could affect reproductive systems, but you would need to ingest it for any effect (and a lot of it apparently).

It's not toxic otherwise. You need very high concentrations: lethal dose is 2.6g/kg. To put that in perspective, table salt is lethal at 3g/kg.


>Adding about half a teaspoon of powdered boric acid to each shoe at least a couple times a week makes a huge difference.

Wouldn't that lead to a powdery build up after a while? Do you need to eventually shake out the powder?

Depends on the shoe and the amount. I mostly wear sneakers and never had any build up. You just put a bit of powder and shake it in the shoe. Humidity will dissolve the powder, some will wick into socks, protecting them as well. If you still see some in the shoe then no need to add more.

Best is to try it and make your own experience. Boric acid is quite cheap.

It dissolves in water. You'd want to spray them down or wash them occasionally, but your sweat would effectively put it in solution and walking would distribute the solution throughout the inside of the shoe. Most probably gets removed by feet and socks each day.

Are you not concerned about testicular atrophy? That's the reason it's banned in the EU...

The studies are done on rats ingesting high doses of Boric Acid, every day for weeks. The Wikipedia page also mentions testicular atrophy was noticed in dogs after ingesting 32mg/kg body weight for 90 days.

That's like a human eating about 2g of the stuff every day, on par with your needed daily intake of salt. That would be a lot of boric acid...

In our case were only concerned with external application and there doesn't seem to be any noted effect there.

you're not going to absorb enough through your feet to have that effect. get a grip.

Would this also help against yellow(ish) toenails?

That sounds like nail fungus. Consult a doctor if you want to treat it effectively.


But would keeping your shoes fungus free keep your toenails fungus free?

Might be worth trying. Might not solve the issue if it's already there but could well help preventing it somewhat, although I don't know what cause this condition though.

I've had fungal infections in the past, between the toes mostly, but it's a thing of the past now. Nothing in the past 5 years.

Have a look at Big Clive's video on "Fixing your feet":


Probably not. Sounds like toenail fungus. I've had it and it is basically only treatable with oral Lamisil - which is nasty stuff, but does work well.

We've been making laundry detergent for our high-efficiency washing machine out of borax, washing soda, and fels-naptha. This is one of the best household hacks we've ever done.

It not only does a better job of cleaning the clothes than Tide and the like (bonus: no perfume smell), it's much cheaper as well and has saved us hundreds of dollars in detergent costs over the last few years.

1 gallon of tide = $15, 5 gallons of home-made detergent = less than $2. The only downside is that powered washing soda is not carried by every grocery store these days. (And it means you need to store 5 gallons of detergent somewhere.)

We use this recipe but we don't bother to boil the bar soap: https://www.mrshappyhomemaker.com/homemade-liquid-laundry-de...

One use I have for borax is making cheap slime to remove dust on tough to clean parts. OLd PCBs with lots of electronics that wont air dust easily, car air vents, etc.

Most common mix is - Dissolve 1 teaspoon of borax in 1/4 cup (2 oz) warm water. - in a separate bowl, Mix 1/2 cup (4 oz) kids glue with 1/4 cup of warm water. - once everything is mixed properly, you can also add food color, glitters and whatnot. I stick to white so I can see the crap I capture and when its saturated properly. - Mix the content of the 2 together a lot

The resulting slime can be used later when sealed properly.

Don’t skip the water-glue mix, it helps with the end result.

You can capture a LOT of dust without creating airborn particles, or have something fun for the kids to play with.

I make this slime with my kids. I also bought some slime meant for detailing cars. I didn't even realize it was basically identical to the slime we had been making until I opened it.

Do you let this dry in place before removing it, or does it just stay together when you press it into dusty surfaces immediately pulling it away without leaving any residue behind?

Depends on the glue used, it might be a little brittle when fresh out, test it on non-critical surfaces. Sometimes I put a little more glue than water, etc. Experiment with fractional mix before going all in.

You do now need to use all the water from the mix if there’s leftover after a long mix.

One minor application not on that list is as an electrolyte in capacitors.


Anecdotally, burst electrolytic capacitors in electronics make very effective ant traps. I don't know which component attracts ants (is it the glycol?), but the boric acid component is an effective insecticide (as OP discusses). Commercial ant products are based on borax as well.


Anecdotally, you *don't* want your electronics to dual-class as ant traps.

Of course, there's Crazy Ants that just love electronics in general.


It seems very weird to me that borax is so widely used in contact with humans in a variety of settings like ocular care and anti foot odor, because I use it as a flux in silversmithing and there are warning labels everywhere about the flux that it's reprotoxic, carcinogenic and mutagenic. Anyone knows why is that? Are my labels overcautious?

I would guess there's more than borax in it:

> Traditionally borax was used as a flux for brazing, but there are now many different fluxes available, often using active chemicals such as fluorides[9] as well as wetting agents. Many of these chemicals are toxic and due care should be taken during their use.


From the toxicity section (https://en.wikipedia.org/wiki/Borax#Toxicity) it seems like the concern is most about ingesting borax in large quantities or breathing in the dust. And also being cautious on potential health affects:

  Since people are already exposed to boric acid naturally through their diets and water, Health Canada advised that exposure from other sources should be reduced as much as possible, especially for children and pregnant women. The concern is not with any one product, but rather multiple exposures from a variety of sources.

The more likely effect seems to be the result (again, as boric acid) on fertility.


"Although it does not appear to be carcinogenic, studies in dogs have reported testicular atrophy after exposure to 32 mg/kg bw/day for 90 days. This level is far lower than the LD50."

The base toxic dosage (on the order of multiple grams per kilogram bodyweight) is the reason it's typically labeled as very safe.

The labels and general knowledge passed from trainer to trainee insist on the reprotoxicity of the flux, which as you point appears to be at exposure levels far below toxic levels. I wonder if the safe label of boric acid for feet is made looking only at the general toxicity of the product, leaving aside potential reproductive issues that might arise with repeated use of small quantities?

Borax flux is a mixture of boric acid and ammonium chloride and then you are dumping it into molten metal where it likely combines with metals and gives off gases.

Kind of different than just boric acid itself?

At least in silversmithing I don't recall flux to contain any ammonium chloride it seems to be a solution of borax alone.

Borax is used in most sturgeon french caviars to preserve it. I guess in small quantities.

Also, disodium octaborate tetrahydrate (aka Tim-Bor / Bora-Care in the US). Roughly: glycol + borax + boric acid.

Spray it on lumber, and it absorbs into the wood, killing termites, powder post beetles, carpenter ants, mold, and algae.

For the lifetime of the lumber, no reapplication necessary.

Cannot recommend it highly enough for exposed crawlspaces / basements in humid climates.

A few here appear to treat borax and boric acid as the same product, which they aren't. For anyone getting any new and exciting ideas, maybe explore the difference and their significance first.

Borax is incredible stuff. I used it as an insecticide in Florida. I could puff it into places behind cabinets and appliances. It doesn't kill by chemical means, but by getting stuck in insect chitin, ripping it apart and then desiccating it. It's safe for pets too. Amazing.

Borax doesn’t do that. It actually affects the nervous system of insects, see here: https://homeguides.sfgate.com/insects-borax-chase-away-kill-...

I think you are thinking of silicon dioxide which does get into the chitin of insects: http://npic.orst.edu/factsheets/degen.html

I remember reading that.

I lived in downtown Baltimore, in a row house.

I had roaches. Not the big, giant, kind, they get in the tropics. These were smallish, basic, tough-as-nails-will-still-be-around-after-the-apocalypse roaches.

When I put out borax, they immediately took out little straws, and started snorting it.

Diatomaceous earth work by getting under the carapace and puncturing the insect - causing dehydration which kills the insect.

I was just in Trona and Boron today - nearly half of the world's borax and boron chemical supply come from these two places in the Mojave. From saline pumped from under dry lakes.

The same places supply much of the soda ash and bicarbonate of soda for the US. Plus sodium sulfate/glauber's salt.

We use it in our pool to raise and buffer the pH without affecting the alkalinity. It is much cheaper than the equivalent "pH up" pool chemicals and we order it from Amazon in bulk. I do wonder what the UPS person thinks when they deliver the huge heavy carton labeled "BORAX" - meth lab?

I use it in my spa and the buffering effect makes the PH so stable I barely have to do anything to it for weeks at a time other than occasional shock and refill the bromine tabs. Really made spa maintenance much easier.

Well, we use boric acid in powder form on carrom boards. It reduces the friction between the wooden board and the coins/striker. I've tried different purpose built carrom board powders, but nothing else has the exact balance between speed and control for me.

Another use is to kill cockroach. I remember an invasion of cockroach in an old flat I was renting, most likely linked to construction works next to our building, I made a mixture of borax+condensed milk, and they ended up disappearing.

I've got a small jar packed with pyrites contaminated gold panning metals from Gympie, if the borax method is simple I'd love to try it.

I actually watched someone do this recently. With the right equipment, it works surprisingly well.

Fantastic stuff for mould suppression. Make a paste and rub it on the wall, you'll have nothing to worry about for months.

This is how they used to get borax out of Death Valley before railroads https://en.wikipedia.org/wiki/Twenty-mule_team

Borax is great for cleaning/degreasing sinks, ceramic and stainless. It also really shines up chrome plated faucets and mirrors. Really anything non plastic in the bathroom.

Works way better than baking soda but does leave a grit behind, so rinse well.

I had great luck with Boric Acid powder to tackle carpet bugs. Nothing else won that war.

The worst thanksgiving menu ever. I can’t find the menu itself (basically

Borax Soup Borax Salad Borax Turkey Desserts Borax)

But it is referenced here


I will go look over metafilter archives, since I imagine that’s where I read this originally.

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