Admissibility of MODVAT credit: external storage allowed with commissioner permission, credit only after inputs received in factory. Manufacturers may obtain permission from the jurisdictional Commissioner of Central Excise to store MODVATable inputs outside the factory, with that storage treated as an extension of the factory premises subject to safeguards to protect revenue. Credit shall be taken in the books only when the entire inputs covered by the invoice are received inside the factory for use in production.