可以濯吾缨

From 《楚辞·渔父》 (Chuci, 'The Fisherman,' attributed traditionally to 屈原 or his circle, 3rd c. BCE). After Qu Yuan laments his exile, the fisherman sings and rows off: 沧浪之水清兮，可以濯吾缨；沧浪之水浊兮，可以濯吾足 (when the waters are clear, I may wash my hat-strings; when muddy, I may wash my feet). Also taken up by Confucius in 《孟子·离娄上》, treating it as the principle that the world decides whether honor is possible. 缨 = the chinstrap tassel of an official's hat, symbol of office.

Always read paired with 可以濯吾足, the pair is the whole point (pure world to official service; muddy world to private life). 濯 (2nd tone) = to wash. 吾 is the classical 'my.'