Small enterprises negatively affect the environment due to the inadequate disposal of manufacturing and raw material wastes generated in production processes; in addition, small enterprises do not often adopt adequate environmental practices due to barriers that include the lack of investment capacity. However, the adoption of cleaner production results in economic and environmental gains. The purpose of this study is to demonstrate how Brazilian small metal mechanical enterprises can identify and overcome barriers with the aim of implementing cleaner production. The research method used multiple cases with data collected by means of interviews and observations. The results allowed us to conclude that cultural and technical barriers negatively affect the adoption of cleaner production in the small enterprises studied. However, cultural and technical barriers can be overcome by means of economic and environmental gains as well as through investment in employee training and in the acquisition of more efficient machines and equipment.