Can you save leftover hair bleach? If not, what’s the best way to dispose of it?

  • Leftover bleach cannot be saved because it loses its effect after sixty minutes. So even if you do, it won’t do you any good. If you use it, you’ll expose your hair to damage.
  • So what you should do is throw it away under water like the toilet, the sink in your bathroom, or the kitchen sink.
  • What you shouldn’t do is throw it away in plastic or cardboard bags, as the chemicals can break the material and spill.


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You’ve just bleached your hair, and you look amazed at how much bleach you have left over. Of course, you just wanted to bleach your ends, and you didn’t really know how much bleach you’d needed.

Just in case, you prepared a lot. Now you have some leftover and you’re sorry to throw it away. After all, you’re an advocate of recycling and reusing.


But this time, you’d better save your environmental values for another time. Because  leftover bleach can’t be saved. 

You cannot keep it under any circumstances.


Not even for your neighbor to use two hours later when she comes home from work. You may be a charitable soul, but all you’ll get is for your neighbor to irreversibly damage her beautiful hair with the leftover bleach.

And we’re not talking about just any kind of leftovers.


I agree with you that most things deserve a second chance. I certainly know it. I invent culinary delicacies with leftovers from lunches and dinners to avoid waste.

But bleach is a different matter. It’s made of chemicals like peroxide and ammonia that can trigger dangerous processes if stored.

It doesn’t matter if you save it to reuse it or if you keep it in your bathroom.


 Leftover bleach should be discarded. It’s a must.  

And it’s no good throwing it in your wastebasket. No!


You must take other precautions. You can’t keep it in the fridge, in the freezer, or in the thermal bag that your boyfriend uses when he goes fishing.

So, my little recycler, stay with me, because I’ll tell you:

  • Why you should not keep the leftover bleach
  • 3 ways to safely and correctly dispose of leftover bleach

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Why you shouldn’t keep the excess bleach

blue bleach

Bleach lasts sixty minutes from the time you prepare it. After applying it to your hair, there’s no further use for it.

Because the rest of the bleach mixture is no good. After sixty minutes, you must discard it.



It’s very simple.  Bleach processes your hair dragging the natural or artificial pigments out of it. 

To make it possible, when peroxide and bleaching powder are mixed, a chemical reaction takes place.

This chemical reaction has a beginning, a process, and an end.


  • The beginning is the time in which you mix the ingredients.
  • The process is the time when the mixture develops on your hair.
  • And the end, tic tac! It’s sixty minutes later.


Then, if you keep the leftover, you’ll dive into uncertain terrain.

Firstly, if you try to use the bleach, say three days later for a second bleaching session, it won’t work. The chemical reaction will be already over.

Also, the residues can be harmful to your hair and toxic to your skin.


Would you take that risk to save a few dollars on bleach?

I don’t think the risk is worth it.

It’s not worth the risk of damaging your hair with a leftover bleach that won’t work and will only harm your hair.


 It’s like keeping food in the fridge for a long time. No matter how long you keep it in the fridge, food has a shelf life. 

Why do you think, for example, some foods can be frozen for six months and others for three?


For safety!

  The same happens with leftover bleach: you shouldn’t keep it due to safety reasons. 

Now you know. Once you mix the ingredients, you must use the mixture in the next sixty minutes and discard the leftover. Believe me, the planet will thank you.

But it’ll thank you even more if you throw it away in the right conditions and places. Do you want to know what they are?


Read on. You’ll learn more about waste recycling today. After all, leftover bleach is just that, waste.


3 ways to dispose of leftover bleach safely and correctly

dispose of hair bleach

Have you convinced yourself that keeping the extra bleach to save a few dollars is a bad idea?


We saved one more hair! Bravo!

So, it’s time you knew the precautions to dispose of it properly, considering the planet and yourself.

We’ll start with your safety.


How do you safely dispose of leftover bleach?

Bleach is a very corrosive mixture. If you’re one of the lucky ones who hasn’t suffered any injuries from improper handling, lucky you!

But believe me, I know people who have suffered skin burns after applying it without gloves or protection.


That’s why you have to handle bleach carefully at all times.

  • When applying it to your hair, wear gloves and a mask as bleach vapors can damage your mucous membranes. If you don’t use protection, your eyes, nose, and throat will feel irritated.
  • When you dispose of the bleach, wear gloves and a mask because it’s still as irritating as when you applied it to your hair.


Very good. You’ve got your gloves on, your mask is on, and you’re ready to dispose of the dye. And you’re overcome with doubt.

Can I dispose of the dye anywhere?


Absolutely not! Negative.

 You can’t throw it in the trash can or in a plastic bag. The chemicals are powerful and they can damage the material.  

Always wearing your gloves, put all the elements you used, plus the excess bleach, under running water.

If you already cleaned the elements you used to prepare the bleach mixture, and you only have to discard the excess bleach, there are three places in your home where it’s safe to dispose of it.


1- You can flush the remaining bleach into the toilet.

Of course, flush the toilet, and if you can, flush it three times. This way, you’ll make sure that the water runs off the chemicals.


2- You can throw the rest of the mixture in the bathroom sink or laundry room.

Let the water run for at least a few minutes to ensure that no trace of the bleach remains on the surface of the sink. Especially if you have small children around.

With children, no precautions are ever enough.


3- You can throw the rest of the bleach in your kitchen sink.

This should be the last option because the kitchen is where we handle food. For safety reasons, it’s always better to avoid this place.

 If you don’t have any other option, make sure that there is no other element in the kitchen sink, and let the tap water run for a few minutes. 


Once you discard the bleach, clean all the elements, such as the plastic container or the brush.

You don’t need to use any special cleaner, as the water instantly neutralizes all the bleaching chemicals.



Today we learned two important lessons:

  • you may not store the leftover bleach under any circumstances
  • and you should dispose of it in the toilet or basin, leaving the water running for a few minutes


Both when applying the bleach and when removing the leftover, you have to protect your skin with gloves. Also, it never hurts to wear a mask to avoid inhaling toxic gases.


As regards bleach leftovers, you can only comply with one of the three R’s (reduce, reuse and recycle)of ecology’s law: reducing. So, next time you decide to bleach your hair, you can consider preparing less bleach.

The leftover bleach cannot be reused nor recycled.

If you follow my tips, the planet will smile with satisfaction.


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