Transitional jobwork relief: no tax where inputs returned within prescribed period, subject to declaration and recovery rules. No tax shall be payable where inputs, semi-finished goods or goods sent for testing or other processes prior to the appointed day are returned to the principal place of business within six months (extendable by the Commissioner up to two months); failure to return within that period makes input tax credit liable to recovery under clause (a) of sub section (8) of section 142, and the exemption requires declaration of goods held by the job worker on the appointed day in the prescribed form, manner and time.