(1) [wash grains of gold out of the sand;(fig) get essentials from large mass of material] 沙里淘金。比喻从大量的事物中选取精华

虽古人糟粕,真伪相乱,而披沙拣金,有时获宝。唐 刘知几

《直书》

(2) 亦作披沙沥金