Musnad Ahmad 1159:1

Abu Kamil narrated to us, Hammad—meaning Ibn Salamah—narrated to us, from Yahya ibn Abi Ishaq, from Sulayman ibn Yasar, that Umar ibn al-Khattab perceived a pleasant scent at Dhu al-Hulayfah. He said, "From whom is this scent?" Muawiyah said, "From me, O Commander of the Faithful." He said, "From you, by my life?" He said, "Umm Habibah perfumed me, and she claimed that she 'perfumed the Messenger of Allah (peace and blessings of Allah be upon him) at the time of his entering into Ihram.'" He said, "Go and swear to her that she must wash it off." So he returned to her, and he washed it off.