In one of the earlier plagues - Moshe is forced to leave Pharaoh's palace to pray to Hashem - because the palace is too full of idolatry. At that time the impurity was too strong. The biggest upshot of the miracles of yetzias mitzrayim was that the kedusha was able to escape from the clutches of the overpowering tumah.
That's why their idols all melted and rotted and crumbled - to show they had no power to block the Jews access to Hashem any longer.
This Pesach imagine all the things that are preventing you from achieving a life of kedusha - and know that they are coming down on seder night !
Hatzlacha !!
