Excise duty on exempted goods packed in exciseble goods

A Company manufacturing Tax Free Goods and the said goods is packed in pouches which created by own machinery i.e. plastic roll to pouches and the said goods is packed and selling to customers. In this case, weather excise duty is applicable on conversion of roll to pouches? if yes what is base of valuation of the said pouches. Becasue the tax free goods are selling which cost includes of packing material.