 By investing in such infrastructure, the Zabbaleen continually upgraded and enhanced their methods of recycling plastic, paper, cardboard, glass, metal, and fabrics.Thus, the city of Cairo and its administration had been able to manage its solid waste at almost no cost to the municipal administration because of such efforts by the Zabbaleen.Hence, the income that the Zabbaleen generate is mainly derived from their recycling and sorting activities, not from the minimal fees (LE 2-4) that they collect from residents.