‘The value of working with this precept [the precept of not intoxicating, but cultivating a clear mind] is not to try to clear the clouds forever, but to come to an understanding that neither the clouds not a clear mind alone is the fullness of life.’ (Deep Hope)
Here is a quote that somewhat typifies how the zen approach differs from the initial Theravadan approach: instead of eliminating the impurities, we do our best to be clear, and also get to experience the effects of clouding.
Shundo David Haye 