Senses
沙里淘金/ 沙裡淘金 to pan for gold from sand
To extract gold from sand by washing it with water.
沙里淘金/ 沙裡淘金 small returns for great effort
To get very little result despite spending a huge amount of time or energy.
沙里淘金/ 沙裡淘金 to select the essence
To pick out the best parts from a large amount of material or to select the best from a mass of people or things