[pái shā jiǎn jīn]   

排    沙    简    金    排：除去；简：选取。拨开沙子来挑选金子。比喻从大量的东西中选取精华。

pái shā jiǎn jīn，拨开沙子来挑选金子。比喻从大量的东西中选取精华。

Obtain gold by washing it from sand and gravel

排山倒海    排沙简金    排患解纷    排沙见金    排除异己