The longevity and performance of oil paint brushes depend heavily on the cleaning agent and method used. Oil paint, which uses a drying oil like linseed oil as its binder, requires a solvent or a specialized surfactant to break down the oil and pigment mixture effectively. Artists must balance the cleaning power of traditional solvents with concerns about personal health, studio ventilation, and environmental impact. The “best” solution is not a single product but a choice that aligns effectiveness with safety and cost, often leading to a two-stage cleaning process.
The Classic Solvent Options
Traditional cleaning methods rely on powerful chemical solvents that quickly dissolve the oil binder in the paint. Gum Turpentine, a natural product distilled from pine tree resin, is a highly effective solvent known for its strong, sharp, pine-like odor. It mixes well with natural oils and resins. However, turpentine evaporates quickly, creating a high concentration of volatile organic compounds (VOCs) in the air, which contributes to its toxicity and potential for respiratory and skin irritation.
Traditional Mineral Spirits, often sold as paint thinner, is a petroleum-derived solvent and a less expensive alternative to turpentine. While considered less toxic than turpentine, it still contains aromatic hydrocarbons that produce a strong, kerosene-like odor and high VOCs. Both classic solvents are flammable and require excellent ventilation to prevent the accumulation of harmful vapors. Their aggressive nature makes them efficient at dissolving paint, but their risks have prompted the development of safer alternatives.
Safer Alternatives and Specialized Soaps
The most common compromise between cleaning power and safety is Odorless Mineral Spirits (OMS), a highly refined version of traditional mineral spirits. The refining process removes most of the aromatic hydrocarbons, reducing the strong odor and toxicity. OMS is a safer option due to its lower volatility and reduced odor, making it the preferred choice for artists working in enclosed spaces. However, “odorless” does not mean “non-toxic,” and proper ventilation is still mandatory, as the lack of smell can lead to overexposure.
Another category of low-toxicity options includes Citrus and Plant-Based Solvents, which often use d-limonene, a compound derived from citrus peels. These solvents are appealing because of their pleasant scent and low toxicity, but they are generally weaker than petroleum-based solvents. Some plant-based cleaners can leave a slight oily residue on the brush, which may affect subsequent paint layers if not thoroughly removed. For this reason, they are often used for initial bulk cleaning rather than as a final rinse.
The safest and most conditioning options are Specialized Brush Soaps, which are non-solvent and water-based. These products contain surfactants and often conditioning oils that emulsify the oil paint, allowing it to be washed away with water. Specialized soaps are not typically used to remove the bulk of the paint, as this would quickly contaminate the soap. Instead, they are used in the final cleaning stage to remove residual solvent and pigment from the ferrule and bristles, helping the brush maintain its shape and pliability.
A Step-by-Step Cleaning Method
A systematic approach ensures the most thorough cleaning and extends the life of the brush. The first step is to remove excess paint by wiping the brush firmly against a rag or paper towel. This mechanical removal minimizes the amount of pigment that needs to be dissolved by the cleaning agent, keeping the solvent cleaner for longer.
The second step involves using the chosen solvent, such as OMS, to dissolve the remaining paint. The brush should be swished gently in the solvent, working the bristles against the bottom of the container to loosen paint trapped near the ferrule. Paint left to dry in the ferrule will cause the bristles to splay and ruin the brush’s shape.
The third and final wash is performed using a specialized brush soap and warm water. The brush is worked into the soap to create a lather, which emulsifies the oil and removes any residual solvent. This process should be repeated until the lather runs completely white and clear, indicating all pigment has been removed.
The final step is reshaping and drying. The bristles should be gently molded back into their original point or chisel shape using the fingers. The brush must then be laid flat or hung head-down to dry, preventing water from seeping into the ferrule and potentially loosening the glue or damaging the wooden handle.
Protecting Your Health and Your Brushes
Working with any solvent requires safety protocols to protect personal health. Even with low-odor options like OMS, proper ventilation is non-negotiable, ideally involving a fan that draws air away from the artist and out of the workspace. Wearing protective gloves is recommended to prevent solvents from being absorbed through the skin, which can lead to irritation and systemic exposure.
Environmental responsibility is a consideration when disposing of used solvents and paint-soaked materials. Solvents should never be poured down the drain, as they are toxic and can contaminate groundwater. Instead, used solvent should be poured into a clearly labeled, airtight container and allowed to sit undisturbed. The paint pigment will eventually settle, allowing the clear solvent to be decanted and reused.
Any solvent-soaked rags or paper towels must be treated as hazardous waste. Oily rags should be stored in an airtight metal container to prevent spontaneous combustion, which occurs as the oil oxidizes. The solidified paint residue and the rags should then be taken to a local household hazardous waste facility for proper disposal.