Mineral spirits, turpentine, and other solvent-based paint thinners are great for thinning out oil-based paints and for cleaning your painting equipment like brushes and rollers.
However, there are varying laws, fines, and punishments from state to state in place if you don’t dispose of paint thinners correctly.
This guide will go through the correct steps so our readers can safely dispose of paint thinners to keep you, your neighbourhood, and the environment safe.
How To Dispose Of Mineral Spirits
You’ll be happy to hear that mineral spirits don't go bad over time, so it's not necessary to dispose of them after every use. Once you’ve finished with your painting project, allow the mineral spirits to settle and when you are ready to use it again, simply pour the clear mineral spirits into a waste-safe container.
You can then put the empty container (with less than 1-inch of paint residue) into the trash. If there’s more than 1-inch of paint residue in the container, we recommend disposing of this in a hazardous waste collection facility.
How To Dispose Of Turpentine
If you have a container that is about to be empty, leave the container in a well-ventilated area so that the turpentine can evaporate. You don’t need to have it at a heat source for it to evaporate; it may cause the container to go up in flames.
This process takes several hours, so allow yourself to have plenty of time. If the container has a lot of turpentine left, then it will need to be disposed of carefully. We recommend bringing turpentine containers to your local hazardous waste facility in this case.
How To Dispose Of Acetone
For small amounts of acetone, you can soak it up with cotton balls and put them into a small garbage bag, tie a knot, and put it with your regular trash. Remember to wash your hands of any remaining acetone after handling cotton balls.
For larger amounts of acetone, we recommend sealing the solvent in a leak-proof container or jar and keeping it away from any open flames. You can then hand this over to the hazardous waste facility so they can dispose of it correctly.
How To Dispose Of Polyurethane
Containers with less than an inch of polyurethane-based paint thinner can be disposed of by leaving the lid off and allowing the product to evaporate. You can then dispose of the empty container with your regular trash. Be sure to leave the lid on, and do not recycle these containers with other plastics as they will contaminate the rest of your recyclables.
For larger quantities of this paint thinner, it must be brought to the household hazardous waste collection facilities in your area. This product is extremely flammable and poses a high risk of air pollution if it’s improperly dumped.
How To Dispose Of Toluene
Toluene is a very toxic chemical and can cause dizziness and confusion if you’re around it for too long. If you are planning on disposing of a lot of this type of paint thinner, we recommend having it collected by a hazardous or household waste collection facility.
You can also consider recycling this paint thinner by pouring the substance into a locked jar and reusing it for a future project. Be sure to label it and keep it out of reach of children. We also recommend wearing protective gear and an appropriate face mask when working with any type of solvent paint thinner.
Why Are Paint Thinners So Dangerous?
You can find some common hazardous ingredients in paint thinners that can cause potential dangers if they are not disposed of correctly. Some of these ingredients are acetone, benzene, methanol, naphthalene, toluene, turpentine, and xylene.
Some of the dangers you can run into if you don’t dispose of paint thinners correctly are:
Can I Re-Use Solvents/Mineral Spirits?
It is wasteful and completely unnecessary to dispose of paint thinners after every use. You can reuse and recycle them so you get more for your money.
If you have leftover paint mixed with paint thinners, or you have a jar of paint thinner for your brushes to clean, simply leave the solvent to sit overnight in a well-ventilated area. The next day, you will see that the paint residue and pigments will settle at the bottom of the containers or jars, and the reusable paint thinner will sit clear on top.
Pour the clear solvent into a second clear container or jar and reseal it for future use. We recommend labelling this new jar with the name of the paint thinner to avoid any confusion in the future and always store it away from children.
Keep the leftover pigments together, and when it’s full, bring them to your local hazardous waste collection facility. Never pour the paint pigment down the drain as it is bad for the environment.
Paint Thinner Disposal FAQs
Can you put paint thinner down the drain?
It is against the law in many cities and states to dispose of paint thinners down the drain as it will run into a body of open water. These solvents contain chemicals that will infect the soil where animals live and can endanger the health of human beings in your area.
Can I pour mineral spirits down the drain?
Mineral spirits are also considered hazardous to the environment and humans as they have a high level of VOCs. We recommend reusing mineral spirits as we’ve explained above or calling your local landfill to see if they can dispose of it for you in the right manner.
How do you best dispose of paint thinner rags?
Rags that are soaked in paint thinner are combustible, so they need to be disposed of correctly. Be sure to place used rags in a sealable metal container and fill it with water. You can then bring the container to a hazardous waste facility.
If you don’t have an appropriate container, we recommend spreading the rags out on a non-flammable surface so the paint thinner can dry out as much as possible before you dispose of them appropriately,
Does paint thinner evaporate?
As paint thinners are highly volatile, they will evaporate, but it takes some time. As we mentioned above, you can evaporate small amounts of products in areas that are well ventilated. Allow yourself plenty of time for the process to take place.
Can paint thinner spontaneously combust?
Absolutely! These rags that are soaked with paint thinner can spontaneously combust and catch on fire. As the rags are beginning to dry, they produce heat. Once you mix this heat with oxygen, they can cause a fire, and fast.
This is why it is important to dry out used cloths and rags on non-flammable surfaces and in a well-ventilated area, so you don't cause any risk of any harm to your home or loved ones.
As you can see, there are many potential dangers when using all types of paint thinners. The best way to dispose of these harmful solvents is to reuse, recycle, or simply give the unwanted paint thinner to someone else who needs it. We hope you have found our tips helpful, and you now know how to dispose of paint thinner correctly.