Whatever has added-on to the basic and fundamental knowledge 'I am' has destroyed its purity. Drop aside everything added-on and only remember the 'I am' in all its purity. You have to really get after it and for that you have to reside in it, dwell on it at all times. In the process you will realize that the 'I am' is dependent and destructible and hence unreal, for the real is independent and indestructible.