- You can keep leftover hair dye and use it another time if and only if you haven’t mixed it with peroxide.
- If the leftover dye has been mixed with peroxide, then you can’t use it again. Your only choice is to toss it.
- Permanent dyes tend to have a long shelf life, in the ballpark of 4-5 years. But, you should always check the date on the package before using any dye.
Many clients at my salon ask me, “Can I use dye again once I’ve opened it?”
The answer is, “Yes, you can use it again, if and only if you haven’t mixed it with peroxide.”
What does that mean?
You mix permanent dyes with peroxide.
Peroxide is what causes the chemical reaction that allows color to penetrate your hair.
Both the tube dyes that professional salons use and box dyes you can find in supermarkets or pharmacies need to be mixed with peroxide.
So, let me ask you a question. What should you do with the dye that you’ve already mixed with peroxide?
- If you’ve already mixed the dye with peroxide, then you cannot use it again another time. Your only option is to throw it away.
- If you didn’t mix the dye with peroxide, then you can save it for future use.
Everything that we’ve talked about so far applies to permanent dye.
What happens if the leftover dye is semi-permanent?
Semi-permanent dyes are a whole different ballgame.
Usually, semi-permanent dyes come in small packets. Only a few of them come in some resealable containers.
- If it came in a container, you can reuse it.
- If it came in a packet, you can’t.
You don’t use peroxide with semi-permanent dyes, instead they react with oxygen, so if they aren’t stored in an air-tight container, they lose their effect, and when you apply it to your hair the next time, the dye won’t do anything.
So now you know what to do if you have leftover dye.
But, as we said before, there are box dyes and dyes that come in tubes.
Each different kind has its own particularities about how to store them, and I’ll tell you about them right now.
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What to do with leftover box dye?
When you go to a beauty store to buy hair dye, there are many options.
One common option is a color kit.
A color kit is a little box that comes with everything you need to dye your hair from start to finish.
- Tube of dye
- Hydrating oil
- Post-color treatment
- And gloves
Oftentimes, you need to touch up your color at the roots, so you shouldn’t prepare the whole tube of dye. If you only prepare half of it, then you’ll have more than enough.
To do this, you should mix half of the tube of color with half of the jar of peroxide with the hydrating oil.
You’ll have approximately half a tube of dye, and half a jar of peroxide left over.
You apply the color according to the instructions, and you’re good to go.
But you’re probably asking yourself, what do I do with what’s leftover?
Well, if you have any of the mixture left, don’t save that!It won’t work anymore after 30 minutes, so it’s not good for anything.
Keep the half-tube of dye and half-jar of peroxide. It would be best if you’re able to store it in the box kit it came in, so that way you have everything all together.
Permanent dye in a tube with peroxide
In a beauty store, you might also have the option to buy the dye tube, the peroxide, and the gloves separately.
It’s an option for women who have a little more experience with dyeing their hair at home.
Before mixing the dye with the peroxide, stop a moment to think about what you’re going to do. How much dye will you need?
Are you planning to dye your whole head, or touch up your roots only?
- If you’re going to do your entire head, you’ll have to use the entire tube of dye and the entire jar of peroxide.
- Now, if it’s just a roots touch up, you should be fine with half of the tube of dye and half of the jar of peroxide.
In any case, and this is very important, you should not keep the leftover mix because, after half an hour, it won’t do anything to your hair.
Peroxide usually comes in airtight jars, so you can keep it as long as you want.
A tip: always keep all of the elements away from heat since peroxide reacts to high temperatures. If it comes into contact with heat, it will lose its effectiveness.
And not only that but since peroxide is a chemical, a jar of it can explode, so you should be very careful not to expose it to the sun or high temperatures.
Okay. Great. We’ve already talked about what to do with the leftovers from permanent dyes that come both in tubes and in a box.
Now I want to tell you a little bit more about semi-permanent dyes.
Can you keep the leftovers from semi-permanent dye?
Semi-permanent dyes are in bright colors.
You apply them to damp hair, and they don’t come with peroxide.
They’re easy to get in pharmacies and hair care stores.
They come in two different forms: packets and containers.
- You can’t keep and reuse the semi-permanent dyes that come in little packets because those dyes degrade with time and through contact with oxygen.
That means once the packet has been open a while, you won’t get as good of results as with a recently opened packet if you use it.
- It’s a different story if we’re talking about semi-permanent dyes that come in jars or plastic containers.
You can keep and use the dye again when it comes in that form because since they have an airtight top, the ingredients won’t degrade, and you’ll be able to use it as many times as you want.
All you have to do is bleach your hair first; remember that to apply any bright color, you should have a buttery blonde color after the bleach before you dye it.
Then, you apply the dye to damp hair, let it sit and rinse.
Afterwards you can keep the leftover dye if it’s in a container, knowing it’s ready to use again.
Remember to keep it away from heat.
Now you know all this, you can save a lot of money since you know that you don’t have to throw away the dye tubes and jars of peroxide that are left over after you dye your hair.
Remember these tips when you’re trying to save some money in your beauty routine.