Musnad Ahmad 509:7

Yunus ibn Muhammad narrated to us, Hammad narrated to us, from ‘Ata’ ibn al-Sa’ib, from Hafs ibn ‘Abd Allah, from Ya’la ibn Murrah, who said: I came to the Prophet, may Allah bless him and grant him peace, while there was a yellow mark of saffron upon me. He said: "Wash it, then wash it, then do not return [to it]." He said: So I washed it, and then I did not return to it.