It is not really a question of getting rid of karmas. When in the morning you wake up, do you have to get rid of all the dreams first? You have been a thief in the dreams, a murderer, a rapist, or a saint…you can be all kinds of things in a dream. Do you have to get rid of all those dreams first? The MOMENT you are awake you are out of all those dreams — they are finished! There is no question of getting rid of them.
That is the essential message of Zen: that you need not be worried about the past karmas; they were all dream acts. Just wake up and they are all finished.