We’ve covered whether hair dye is environmentally friendly, but what are you supposed to do when you have leftover hair dye?
Most hair dyes are made from synthetic chemicals which can be harmful to the environment. Because of this, hair dye is classed as hazardous waste in many places. You should dispose of leftover hair dye as hazardous waste to avoid harming the environment. Swapping to plant-based hair dye to be more eco-friendly and reduce hazardous waste.
The most eco-friendly way to dispose of leftover hair dye is to reuse it or give it to someone who will use it.
Once your hair dye is all used up, consider making the switch to vegan hair dye to reduce your use of hazardous hair products.
How to dispose of leftover hair dye properly and in the most eco-friendly way possible
One of the first things you should know and do with leftover hair dye is to check local waste regulations about hair products (like hair dye, hairsprays, and hair bleach) to make sure you know how it can be disposed of.
Hair dye is typically classed as a hazardous waste product like other hair products. This means it needs to be disposed of properly according to local rules for hazardous waste.
Most hair dyes contain harmful chemicals like p-Phenylenediamine (PPD) shouldn’t be disposed of down a drain because it has the potential to harm aquatic life.
Thermo Fisher Scientific’s safety data sheet on p-Phenylenediamine determines that it is “very toxic to aquatic life with long-lasting effects” and its water solubility enables it to be mobile through the aquatic environment. While this is specific to PPD on its own, it’s important to recognize that this is just one chemical present in typical, non-vegan hair dyes, and is why hair dye is considered a hazardous waste product.
Once you’ve identified the local laws and regulations for hazardous waste, you should work out how you can take it to the proper waste center or contact your local hazardous waste collection unit.
Remember that hair dye should only be disposed of as hazardous waste, not as your usual household waste. If you throw the hair dye out with your normal trash, it will make its way to the landfill and will contribute to the toxic waste already there.
If you’ve used up all of your hair dye, make sure to check if the bottle can be recycled and give it a quick rinse.
What can you do with leftover hair dye?
Sometimes a product just doesn’t work for you or you’re no longer interested in dyeing your hair that color. Instead of chucking it away, try finding out if anyone wants the rest of your hair dye instead.
Maybe a friend wants to see what their hair would be like in that color, or someone has mentioned they’d love to try it sometime.
You can also check if there are any places that take donations of hair dye, like shelters or care homes. Always make sure that they can accept and are willing to take the product before just dropping it off.
If you’re going to use the same hair dye again, try and use up as much as possible before ordering more.
Once you’ve opened the new bottle, you can carefully add your leftover dye to the new bottle, or just open both and use up the rest of the first bottle before moving onto the next. You could also go for an ombre or gradient with different colored dye by using up your remaining dye.
Some hair dyes (especially vegan dyes) can even be mixed together to create different colors.
If you’re not using a vegan dye or a hair dye that mentions mixing colors, double-check that you can safely mix your hair dyes. Different companies often use different chemicals, so it’s better to be safe than waste all your hair dye.
Swap to plant-based hair dye to reduce further waste
Plant-based hair dyes are far less harmful to the environment, as they use natural and eco-friendly materials instead of synthetic chemicals.
There are more vegan hair dyes out there than ever. Swapping to plant-based hair dye will reduce chemical waste and enable you to happily keep dyeing your hair with minimal impact on the environment!
You can even make your own natural hair dye. Earth911 suggests lemon juice and chamomile tea to lighten hair, while beet and carrot juice can make red hair.
It takes a lot longer to take effect, but there are DIY solutions out there to look into!
How long does leftover hair dye last?
Most manufacturers say that unopened hair dye doesn’t expire. Though after three years hair dye is less effective.
You can tell if hair dye is expired if it’s contaminated by any bacteria or fungi, which will usually give it a bad smell.
Make sure to properly seal your hair dye after every use to avoid spillage and degradation. Storing hair dye somewhere hot, like in direct sunlight, can also affect it.
Some hair dye containers include a period-after-opening symbol, which looks like a cylindrical container with its lid open and a number written over it. For instance, ‘6M’ indicates that after opening the container you have six months to use the dye before it will no longer be as effective.
Some hair dyes don’t come with expiration dates, but you should always make sure to store them in a cool dry place and not in direct sunlight.
If you do use expired hair dye, don’t expect the results to be as effective. You may also experience some scalp irritation or even an allergic reaction, depending on what kind of hair dye you’re using. Less commonly, you might experience hair damage or even hair loss.
When mixing hair dye, you should only mix as much as you need, as the mixed hair dye will only work properly for up to two days after mixing. Some advise that it only lasts up to 30 minutes.
It’s true that when exposed to air oxidation begins to take place, which will drastically reduce the effectiveness of the hair dye. Once you add a developer, like peroxide, you only have 30 minutes to use the hair dye. If you have some mixed hair dye leftover, pack it away in a packet and store it in a cold place.