Non availment of input credit: self declaration ok for exempt exports; merchant exporters may rely on manufacturer certificate. Where exported goods are unconditionally exempt from Central Excise duty, a self declaration of non availment of Modvat may be accepted; for merchant exporters of non exempt goods, if the Shipping Bill discloses the supporting manufacturer's name and address and a certificate in favour of that manufacturer states it did not avail Modvat on inputs used, the merchant exporter need not produce a separate certificate of non availment.