Board Thread:Warhammer 40k General Discussion/@comment-24944355-20140619234937/@comment-26937526-20150127170956

I do not know, maybe they are unkillable by normal means, but can be killed in certain ways.

Like in one thing I have read to kill one type of monster it takes, dealing a certain type of damage to them, cut its head from its body using a weapon made from certain type of materiel, then You must similarly destroy the heart. THEN you must then burn the body and the head separately, scatter the ashes from the body over a natural source of clean and uncorrupted running water, then mix the ashes from the head in holy water, and bury the head ashes in holy ground.

It is a long and hard thing to do, but it is one of three of the only ways to kill one, maybe it is the same for Perpetuals? Hopefully it is not that hard, maybe it just takes a weapon made from certain type of materiel or getting rid a the remains in a certain way or something.