披沙揀金 (pīshā-jiǎnjīn)

1. 沙里淘金。比喻從大量的事物中選取精華 wash grains of gold out of the sand;(fig) get essentials from large mass of material
   • 雖古人糟粕,真?zhèn)?/a>相亂,而披沙揀金,有時獲寶。——唐· 劉知幾《直書》
2. 亦作“披沙瀝金”