Paint thinner and related solvents can contaminate groundwater or cause a fire if thrown in the household trash. Most jurisdictions classify them as hazardous substances and need residents to dispose of them safely and carefully to protect the environment and themselves.
Rags soaked in paint thinner may combust in the air, causing a serious and dangerous fire. Place them in a metal container with a tight lid, fill with water and bring it to a hazardous waste collection area.
There is no need to throw out paint thinner after one use. After soaking tools or brushes, leave the paint thinner to sit in a sealed glass container. Over time, the paint and either contaminant will settle at the bottom. This can happen from a couple of days to several months depending on how dirty the paint thinner is.
Once the dirt has settles to the bottom, pour the clean top layer through coffee filters into a clean glass jar. Leave some space at the top of the new jar, seal it tightly, and label it properly.
Always wear heavy rubber gloves when handling paint thinner.
Then leave the container open and let dry in a well-ventilated area. Add sawdust or sand to speed up drying. Keep this container out of the reach of pets and children, and away from flame, heat, and flammable materials.
Once the material is completely dry and solid, wrap the paint thinner in the newspaper, then seal it in a plastic bag. You can throw it away in household trash.
You can use regular household trash if there is less than one inch (2.5 cm) of residue inside the container, and it has dried completely. Do not put them in a recycling bin.
The easiest way to get the removal of unused paint thinner is to find someone who needs it. Offer it to a friend or neighbor, or donate it to a local organization that can use it for renovation projects.
Many municipalities have permanent sites available only for drop-off of hazardous materials such as paint and paint thinner. Search for facilities in your nearby area by contacting your local government.