Musannaf Ibn Abi Shayba 35:431

Abu al-Ahwas narrated to us, from Abu Ishaq, who said: A man from the tribe said to Abu Maysarah: "I become in a state of janabah (major ritual impurity) in my garment, and I look, but I do not see anything." He said: "When you perform ghusl (ritual bath), then wrap yourself in it while you are wet, for that is sufficient for you."