Eco-Tips: How To Dispose of Paint Thinner Safely and Responsibly

Paint thinner is a hazardous chemical used in the painting and decorating industry. While it is useful for diluting and cleaning up after painting projects, it is also highly flammable and toxic. As such, proper disposal of paint thinner is essential to ensure safety and environmental protection. Improper disposal of paint thinner can cause serious damage to the environment and put people’s health at risk.

how to dispose paint thinner
How To Dispose of Paint Thinner Safely

This article will provide information on how to dispose of paint thinner safely and responsibly. We will discuss the importance of using the right container, the most suitable method for disposal, and the potential risks of improper disposal.

Additionally, we will provide tips on how to reduce the amount of paint thinner used and how to properly store it.

Paint Thinner and Its Composition

Paint thinners are a type of industrial solvent used to thin or reduce the viscosity of paint or varnish and aid in the application of a desired finish. They are also used to clean up after painting and to remove paint from surfaces prior to the application of a new coating.

Paint thinners are composed of a variety of chemical compounds, with many of the components dependent on the particular type of paint or varnish being thinned. Let us elaborate more in the following points.

1. Different Types of Paint Thinners

There are different types of paint thinners available on the market, and each type is designed for a specific purpose. Understanding the different types of paint thinners can help you choose the right one for your painting project and help you dispose of it properly.

Paint Thinner

Typically, substances used to thin, diluted, or clean oil-based paints are referred to as “paint thinners.” These paint solvents are obtained through the distillation of petroleum, natural resins, and synthetic or organic oils. This is the reason the solvent is frequently used to thin oil-based coatings.

Water-based coatings can also be thinned with them, but you should only do so with water-based paint thinners.

paint thinner
Source: Pinterest (@bobvilahome)

Lacquer Thinner

A thinning agent primarily used to thin lacquer and other sealants or top coats like varnish is known as lacquer thinner, often referred to as cellulose thinner. It is produced by mixing many paint solvents, such as acetone, xylene, toluene, butyl acetate, and other substances. 

Instead of removing paint from brushes or rollers, this thinning compound is better suited for thinning paints. This is due to the lacquer thinner’s strength, which can occasionally cause damage to wool and other flexible or delicate textiles.

However, lacquer thinner can assist in cleaning paint brushes, hard surfaces like concrete or masonry, and lacquer residue, oils, and grease.


Another high-quality thinner is naphtha. Enamel, varnish, and wood stains are among the oil-based treatments and sealants that it is most suited for thinning. This is due to the fact that synthetic resins and petroleum distillation are both used to make naphtha. The thinning component is therefore not very effective at thinning water-based paints.

Although there are naphtha thinners, other thinners, such as lacquer thinner, also contain the solvent in their formula. Naphtha quickly evaporates from the coating, which causes it to dry very quickly. As a result, it is less likely to separate the particles or damage the paint.


Ultimax is the principal manufacturer of the thinner xylene. But as a solo thinner, it is hardly ever utilized. Other thinners frequently contain xylene as a component. To thin sealants like varnish and other wood stains, xylene is still effective and strong enough.

White Spirits

Paint thinner called white spirits is typically utilized for cleaning. It can thin water-based paints like latex but not oil-based paints because of its strength. White spirit, on the other hand, is a stable solvent, making it possible to thin oil-based paints or sealants by combining it with other thinners like mineral spirits.

White Spirits
Source: Pinterest (@toolstationUK)

Denatured Alcohol

Water-based paints and shellac stains are primarily thinned with denatured alcohol. Additionally, you can use it to clean painting tools both before and after use. It is one of the safest thinners and is deemed to be safe for use. Oil-based paints cannot be thinned or diluted with it, though.

Mineral Spirits

One of the best thinners on the market is mineral spirits. It is compatible with sealants, clear coatings, and oil-based paints. Mineral spirit is created by distilling petroleum and then adding some additional chemical ingredients. Its composition is comparable to turpentine. Water-based paints cannot be thinned with it, though.


Water can be used to thin water-based paints. However, you shouldn’t use it to thin out oil-based paints or sealants because doing so will reduce the finish’s clarity and viscosity. Additionally, it will prevent them from adhering strongly or drying uniformly.

2. Chemical Composition of Paint Thinner

The chemical composition of paint thinner can vary depending on the type of solvent used. Paint thinners typically contain organic solvents, which are used to dissolve or thin out paint, varnish, or other coatings. Some of the common solvents used in paint thinner include:

Mineral Spirits

Mineral spirits are a petroleum-based solvent that contains a mixture of hydrocarbons, including alkanes, cycloalkanes, and aromatic compounds. This is a common type of paint thinner used to clean brushes, thin oil-based paints, and remove paint from surfaces. 

Mineral Spirit
Source: Pinterest (@davidf3612)


Turpentine is a solvent that is obtained from the resin of pine trees. It contains a mixture of terpenes, which are organic compounds that are responsible for its strong odor. It is highly flammable and has a strong odor, which can be harmful if inhaled.


Acetone is a colorless, volatile solvent that belongs to the family of ketones. It is composed of carbon, hydrogen, and oxygen atoms and has a distinctive sweet smell. Acetone is a powerful solvent that is often used for cleaning and degreasing surfaces. It is also used as a paint thinner for some types of paint, but it can dissolve some plastics and rubber.

Methyl Ethyl Ketone (MEK)

MEK is a ketone solvent that is composed of carbon, hydrogen, and oxygen atoms. It is a colorless liquid with a sweet, fruity odor. MEK is a strong solvent that is commonly used as a certain type of paint thinner, such as epoxies and polyurethanes. It is highly flammable and can cause skin and eye irritation.


Xylene is a colorless, flammable liquid that is composed of aromatic hydrocarbons. It has a sweet, fruity odor and is used as a solvent for paint, ink, and other coatings. Xylene is a strong solvent that is used as a thinner for certain types of paint and as a cleaner for surfaces. It has a high level of toxicity and can cause health problems if inhaled or ingested.

3. Toxicity of Paint Thinner Ingredients

The ingredients in paint thinner can be highly toxic and potentially harmful to human health and the environment. Here are some of the common chemical ingredients in paint thinner and their associated risks:

Aromatic Hydrocarbons

Aromatic hydrocarbons are compounds found in paint thinners like xylene and toluene. Exposure to these compounds can cause headaches, dizziness, nausea, and other health problems. Chronic exposure can lead to more serious health issues, including kidney and liver damage, and may increase the risk of cancer.

Toxicity of Paint Thinner Ingredients
Toxicity of Paint Thinner Ingredients

Stoddard Solvent

Paint thinner (as Stoddard Solvent) has an OSHA 8-hour time-weighted exposure limit of 500 parts per million (ppm). Paint thinners are not particularly dangerous because the OSHA limit for exposure to acetone (nail polish remover) is divided in half.

Despite having a somewhat pleasant smell, paint thinner fumes can irritate the eyes, nose, and throat and, if inhaled in large enough quantities for an extended period of time, as might be the case in a factory or enclosed room, cause nausea and/or dizziness.


Ketones like acetone and Methyl Ethyl Ketone (MEK) are used in paint thinners as solvents. Exposure to ketones can cause irritation to the eyes, nose, and throat, and can lead to headaches, nausea, and dizziness. Long-term exposure can cause liver and kidney damage.

Aliphatic Hydrocarbons

Aliphatic hydrocarbons are compounds found in paint thinners like mineral spirits. Exposure to these compounds can cause irritation to the skin, eyes, and respiratory system, and can lead to headaches, nausea, and dizziness. Long-term exposure can cause nerve damage.

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The Risks of Improper Paint Thinner Disposal

Improper disposal of paint thinner can have serious environmental impacts and health consequences. Let us explain some of the risks associated with improper paint thinner disposal:

1. Environmental Hazard

Pouring paint thinner down the drain or into the ground can contaminate groundwater and soil. This can harm aquatic life and the drinking water quality. Moreover, when paint thinner is not disposed of properly, it can evaporate into the air and contribute to air quality pollution. This can harm human health and the environment.

The World Health Organization (WHO) has reported a 20%-40% increased risk of certain types of cancer (in particular lung cancer) for those who come into regular contact with, or work with paint. 

how to dispose paint thinner
Environmental Hazard for The Risks of Improper Paint Thinner Disposal.

2. Health Hazard

Exposure to paint thinner can cause a range of health problems, including skin irritation, respiratory issues, and organ damage.

According to a study from Indian Journal of Occupational and Environmental Medicine (IJOEM), thinner sniffing causes damage to the brain, kidney, liver, lung, and reproductive system. Improper disposal of paint thinner can increase the risk of exposure for people and animals.

3. Fire Risks

Many paint thinners are flammable and can pose a fire hazard if not disposed of properly. If paint thinner is poured into a trash can or dumpster, it can ignite and cause a fire. According to study from Medicine Science, the mortality rate of paint thinner burns is 12.7%.

Steps for Safely Paint Thinner Disposal At Home

Paint thinner is a hazardous chemical that can be damaging to both the environment and your health if not properly disposed of. Fortunately, with a few simple steps, you can safely and responsibly dispose of paint thinner at home.

  • Wear protective gear such as gloves, safety glasses, and a respirator to avoid contact with the paint thinner.
  • If you have a small amount of paint thinner left over, pour it into a lidded container and take it to your local disposal options. Or, set up a containment area on the ground outside by using kitty litter, sand, or absorbent materials. 
  • Carefully pour the paint thinner into the containment area and spread it out evenly to ensure that it is absorbed. Once the paint thinner has been absorbed, cover the area with plastic sheeting to prevent any further contamination.
  • Place the paint thinner in a sealed, non-breakable container such as a plastic jug or bucket.
  • Contact your local hazardous waste disposal facility to inquire about proper disposal procedures. Follow the disposal guidelines provided by the facility, which may require special containment, labeling, and transportation of the hazardous material.
  • Never pour paint thinner down the drain, into storm drains, or into the ground.
  • Never mix paint thinner with other chemicals, as this can create hazardous fumes.
  • Never burn paint thinner.

Alternative Ways to Dispose Paint Thinner

Paint thinner is a hazardous material that should be disposed of properly. It should never be poured down the drain or thrown in the trash as it can contaminate water sources and harm the environment. Here are some alternative ways to dispose of paint thinner:

1. Reusing Paint Thinner

If you have used paint thinner for a small project, you can reuse it by allowing the paint particles to settle to the bottom of the container and pouring the clear liquid on top into a clean container. You can use it again for another project.

Reusing Paint Thinner As Alternative Ways To Dispose Paint Thinner
Source: Pinterest (

Moreover, you can leave the paint thinner in a well-ventilated area, like outside or in a garage, to let it evaporate over time. This may take a while, but it is a safe and effective way to dispose of it. Once it has completely evaporated, the container can be recycled.

2. Storing Paint Thinner Safely

Store paint thinner away from heat and open flames. Paint thinner is highly flammable, so it is important to have a safe storage and keep it away from any heat sources, such as furnaces, stoves, and space heaters. Moreover, store paint thinner in a cool, dry area. Choose an area that is well-ventilated, such as a shed or garage.

In addition, place paint thinner in a labeled, airtight container. Select a storing container that is made of metal, glass, or plastic, and make sure it has a tight-fitting lid. Clearly label the container with the contents and the date it was purchased.

Eco-Friendly Alternatives To Paint Thinner

When it comes to painting and refinishing furniture, paint thinner is often an essential tool. But paint thinner is a known pollutant that can be hazardous to both the environment and your health.

how to dispose paint thinner
Source: Pinterest (

Fortunately, there are numerous eco-friendly paint thinner alternative solvents that are both safe and effective, here they are: 

1. Soy-based Solvents

Soy-based solvents are made from renewable resources and are biodegradable. They work in a similar way to traditional paint thinners but are much less toxic.

2. Citrus-based Solvents

Citrus-based solvents are good eco-friendly paint thinner alternative solvents. They are made from natural ingredients and are biodegradable. They have a pleasant citrus smell and are safe to use indoors. The Real Milk Paint Company is an example of a natural alternative to a paint thinner made of citrus solvents.

3. Water

In some cases, you may be able to use water to thin out water-based paints instead of using a solvent. This is an easy and eco-friendly way to thin paint. Tikkurila is an example of eco-friendly water based paint thinner.

4. Oil

For oil-based paints, you can use vegetable oil or linseed oil as an eco-friendly alternative to paint thinner. These oils can be mixed with the paint to thin it out and they also have the added benefit of nourishing and conditioning the paintbrushes. Sennelier Green for Oil Solvent is an example of paint thinner made from vegetable oils.

how to dispose paint thinner
Source: Pinterest (@artdepartment

5. Pressure Washing

If you’re working with a surface that can be pressure washed, this is another eco-friendly way to remove paint without using solvents. Pressure washing uses water at high pressure to remove paint, and it can be a very effective method for larger surfaces.

The Future of Paint Thinner Disposal

The future of paint thinner disposal is likely to be more focused on sustainability and environmentally friendly solutions. As people become more aware of the harmful effects of traditional paint thinner on the environment and their health, there is a growing demand for safer, more sustainable alternatives.

There may be a shift towards using more eco-friendly alternatives to paint thinner in the first place, such as the soy-based and citrus-based solvents mentioned earlier. As more people become aware of the availability and benefits of these products, they may become more widely used, reducing the demand for traditional paint thinner and the need for safe disposal methods.

Citrus-based Solvent Cleaner
Source: Pinterest (@houzz)

Another possibility is the expansion of existing hazardous waste disposal programs, such as  Household Hazardous Waste Depot or a Special Waste Drop-off Day.

They would provide individuals and businesses with a safe and convenient way to dispose of paint thinner and other hazardous materials. This could involve more community-based programs that make it easier for people to access safe disposal services.

Final Thought

When disposing of paint thinner, it is important to be aware of your local regulations and follow them closely. It is also important to remember that paint thinner is a hazardous material and should be disposed of properly at a designated facility.

Never pour paint thinner down the drain or into the environment, as it can be harmful to people and wildlife. By being mindful of how we dispose of paint thinner, we can take a step towards creating a more sustainable and environmentally-friendly future.

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FAQs (Frequently Asked Questions)

Is paint thinner hazardous waste?

Paint thinner is not classified as hazardous waste. Paint thinner is considered a hazardous material because it is flammable, volatile, and has the potential to be harmful to humans, animals, and the environment.

Moreover, paint thinners are considered a household hazardous waste and should be disposed of properly. If you are looking for tips on how to dispose of paint thinner, you can read the article above.

Is paint thinner toxic to breathe?

Yes, paint thinner is highly toxic to breathe because it contains Volatile Organic Compounds (VOCs) that can cause lung irritation and damage, as well as headaches, dizziness, and other symptoms.

Long-term exposure to VOCs can cause a variety of health issues, including cancer. You can check the article above for more tips on how to dispose of paint thinner properly.

Is it OK to pour paint thinner down the drain?

No, it is not OK to pour paint thinner down the drain. Paint thinner is a hazardous material and can contaminate water sources and be toxic to wildlife.

It also has the potential to damage the pipes in the drain. Please read the article above for more ways on how to dispose of paint thinner safely and responsibly.

Can you pour paint thinner on the ground?

No, you should not pour paint thinner on the ground. Paint thinner is a hazardous chemical that can leach into the soil and contaminate nearby water sources, and it can also be toxic to plants and animals.

You can follow our tips on how to dispose of paint thinner properly in this article.

Do you need a mask when using paint thinner?

Yes, you should always wear a mask when using paint thinner. Paint thinner contains chemicals that can irritate your skin, eyes, and lungs if inhaled or absorbed through the skin. It is also highly flammable, so a mask can help protect you from inhaling any fumes that might be released.