Sunan an-Nasa'i, Book 3, Hadith 20 (In-Book) ⓘ
It was narrated that Muhammad said: "Umm 'Atiyah said: 'We used not to regard yellowish and brownish discharge as anything important.'"
أَخْبَرَنَا عَمْرُو بْنُ زُرَارَةَ، قَالَ أَنْبَأَنَا إِسْمَاعِيلُ، عَنْ أَيُّوبَ، عَنْ مُحَمَّدٍ، قَالَ قَالَتْ أُمُّ عَطِيَّةَ كُنَّا لاَ نَعُدُّ الصُّفْرَةَ وَالْكُدْرَةَ شَيْئًا .
also referenced under: Hadith 368 (Reference) & Volume 1, Book 3, Hadith 368 (DarusSalam)