At the end of June 1947, Levi suddenly left DUCO and teamed up with an old friend Alberto Salmoni to run a chemical consultancy from the top floor of Salmoni's parents' house. Many of Levi's experiences of this time found their way into his later writing. They made most of their money from making and supplying stannous chloride for mirror makers, delivering the unstable chemical by bicycle across the city. The attempts to make lipsticks from reptile excreta and a coloured enamel to coat teeth were turned into short stories. Accidents in their laboratory filled the Salmoni house with unpleasant smells and corrosive gases.