How To Dispose Of Paint Thinner (Safely & Legally)

Mineral spirits, turpentine, and other solvent-based paint thinners are great for thinning 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 neighborhood, and the environment safe. 

How To Dispose Of Paint Thinner

How To Dispose Of Mineral Spirits 

You’ll be happy to hear that mineral spirits are paint thinner that 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 glass container or fireproof container

You can then put the empty paint thinner containers (with less than 1-inch of thinning oil based paints residue) into the regular household trash. If there’s more than 1-inch of paint residue in the fireproof container, we recommend disposing of this in a hazardous materials at hazardous waste center.  

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 this unused paint thinner containers at a heat source for it to evaporate; this unused paint thinner 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 center or hazardous waste disposal site 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 or plastic bag, tie a knot, and put it with your regular trash or household trash. Remember to wash your hands of any remaining acetone after handling cotton balls. 

For larger amounts of this type of used paint thinner, we recommend sealing the leftover paint thinner in a leakproof container or glass jar and handling paint thinner away from any open flames. You can then hand this leftover paint thinner or paint sludge or sludge remains liquid y over to the hazardous waste facility or hazardous waste disposal site so they can dispose of this pour paint thinner 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 paint thinner empty container in your regular trash or toss emptied containers. 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 leftover paint thinner or paint sludge, it must be brought to the household hazardous waste collection facilities in your area. This pour paint thinner and paint sludge 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 used paint thinner, we recommend having it collected by a hazardous materials or household waste collection facility. 

You can also consider recycling this paint thinner or paint sludge by pouring the substance into a locked glass jar and reusing it for a future project. Be sure to label this pour paint thinner 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.  

young women in medical mask

Why Are Paint Thinners So Dangerous?

You can find some common hazardous ingredients in paint thinners that can cause potential dangers if these clean oil based paints thinners are not disposed of correctly. Some of these ingredients are acetone, benzene, methanol, naphthalene, toluene, turpentine, and xylene paint thinner. 

Some of the dangers you can run into if you don’t dispose of paint thinner or clean oil based paints correctly are:  

  • Potential dangers to human health
    Paint thinners commonly contain hydrocarbons, and if you come into contact with these, you can become extremely ill. Symptoms of paint thinner poisoning are burning in the stomach, mouth, or throat, blue lips, and shortness of breath.
  • Potential dangers to animals
    Animals can inhale or even digest paint thinner if it’s not disposed of correctly. Improper handling paint thinner can cause animals in your area to develop pneumonia or severe respiratory infections. 
  • Potential dangers to the natural environment
    An important environmental impact of improper disposal of paint thinner is on our natural environment. As paint thinners have a high count of VOCs (volatile organic compounds), they can pollute the air and form ground-level ozone (smog). 
poison sign

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 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 paint thinner into a second clear container or jar and reseal it for future use. We recommend labelling this new jar of paint thinner 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? 

No, you can not put paint thinner down the drain. This is prohibited many cities and states due to its potential to contaminate bodies of water. Paint thinners are composed of chemicals that can pollute the soil and endanger the health of animals and humans residing in the area.

Can I pour mineral spirits down the drain? 

No, you can not pour mineral spirits down the drain. This is because mineral spirits are hazardous to the environment and humans as they have a high level of VOCs.

How do you best dispose of paint thinner rags? 

To dispose of paint thinner rags, place the used rags in a sealable metal container filled with water and then take them to a hazardous waste facility. If you don't have access to a suitable container, an alternative is to lay the rags on a non-flammable surface, allowing the paint thinner to evaporate as much as possible before disposing of them properly.

Does paint thinner evaporate? 

Yes, paint thinners can evaporate because they are highly volatile. You can evaporate small amounts of paint thinner in areas that are well ventilated but this process does take time.

Can paint thinner spontaneously combust?  

Absolutely! The 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.


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.