The sun's light is not destroyed, but merely deflected by the clouds and mists. The pure mind possessed by all sentient beings is also like this, in simply being covered by the layered clouds of discriminative thinking, false thoughts, and views. 

If one can just distinctly maintain awareness of the mind and not produce false thought then the Dharma sun of nirvana will be naturally manifest. Therefore, it is known that one's own mind is inherently pure. 

 - Hung-jen (605-651) courtesy of dailyzen.com 

I often tell my clients that the phrase " just do it" minimizes the challenges and struggles  of  life. I am not sure if anyone “can just distinctly maintain awareness of the mind".  I am sure that the attempts to maintain awareness of the mind is the heart and soul of cultivating mindfulness.  Discriminative thinking,  false thoughts, and views are with me everyday and every night. When I am able to catch myself thinking in any of these ways I return to a distinct awareness of the mind.  Then life comes along and yanks me out of my reverie to deal with some unpleasant task. It occurs to me that if I know my mind is inherently pure what do I do with all this other stuff that keeps getting in the way? I wonder if the answer is in the metaphor of the clouds ability to deflect the sun's light. The light is still there even though it is not visible at the moment.  My false thoughts only deflect the Dharma sun of nirvana. The light is always there and when it is revealed I experience a reconciliation with my  discriminative  thinking. Even better I come away with a new piece of wisdom that will stay with me always.