Exemption for job work services where client-supplied materials returned for use in manufacture if excise duty payable. Exempts the taxable service of production or processing of goods as job work from service tax when goods are processed using client-supplied raw or semi-finished materials and returned to the client for use in manufacture of other goods on which excise duty (other than nil-rate or wholly exempt duty) is payable; defines production or processing as working on inputs to complete part or whole of production provided it does not constitute 'manufacture' under the Central Excise Act.