Excise on capital goods?

Dears,

I have come across a querry. Plz help me....

A company bought a machinery (Capital goods) & paid Excise duty thereon. Now, the machine is used for manufacturing an excisable goods, & a non-excisable goods. How to avail Cenvat Credit in the following case?

Further, if company doesnt maintain proper books for such, what would be the impact? Will your answer differ from the above?

Thanks & regards,

Nitesh Choraria