"Although it is arduous to sift through a thousand times and filter ten thousand times, one must blow away all the wild sand to reach the gold."

千淘万漉虽辛苦，吹尽狂沙始到金。

~ Liu Yuxi (刘禹锡, 772-842), Tang Dynasty Poet, Lang Tao Sha (《浪淘沙·其八》)