AbstractThe use of toxic petroleum‐based heavy oils is common in industrial processes. The cleaning of machines, equipment, and other surface covered in these oils is achieved with expensive products that are often also toxic and harmful to both the health of workers and the environment. The present paper proposes the development of a sustainable biodetergent made from plant‐based materials. Tests were performed to determine the properties of the biodetergent in terms of its surfactant and emulsifying capacities, stability, toxicity, and the removal of heavy oil from glass plates and metallic surfaces. The formulation was composed of a natural solvent (cottonseed oil), a plant‐based surfactant agent (saponin), and two natural stabilizers (carboxymethylcellulose and glycerine). The formulation was stable, nontoxic, and highly efficient, removing 100% of the heavy oil from glass and metallic surfaces. This solution developed in this study could be used in diverse industries with the need to clean machines and parts encrusted with oil and grease as well as the cleaning of floors covered with petroleum‐based residues. A preliminary analysis of the economic feasibility of using the detergent was carried out at a Brazilian power plant. Besides the reduction in environmental impact due to the use of a nontoxic, biodegradable product as well as the reduction in health risks to workers associated with toxic cleaning products, this new product can have a considerable impact on the market as an environmentally friendly solution.