Duty exemption for copper products produced from exported reverts allows relief based on toll processing costs plus insurance and freight. Exempts copper cathodes, wire bars and wire rods produced from exported copper reverts used for toll smelting or toll processing from customs duty and additional duty to the extent such duty exceeds duties computed on a value equal to toll smelting or processing costs (labour, material excluding exported goods, other payable charges) plus insurance and freight both ways; relief is conditional on import within one year of export and on production of sufficient evidence showing the goods were obtained by the toll processing of the exported reverts.