Sunan an-Nasa'i, Book 8, Hadith 41 (In-Book) ⓘ
It was narrated that Anas bin Malik said: "The Messenger of Allah saw some sputum in the Qiblah of the Masjid, and he became so angry that his face turned red. Then a woman from the Ansar went and scratched off, and put some perfume in its place. The Messenger of Allah said: 'How good this is.'"
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا عَائِذُ بْنُ حَبِيبٍ، قَالَ حَدَّثَنَا حُمَيْدٌ الطَّوِيلُ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ رَأَى رَسُولُ اللَّهِ صلى الله عليه وسلم نُخَامَةً فِي قِبْلَةِ الْمَسْجِدِ فَغَضِبَ حَتَّى احْمَرَّ وَجْهُهُ فَقَامَتِ امْرَأَةٌ مِنَ الأَنْصَارِ فَحَكَّتْهَا وَجَعَلَتْ مَكَانَهَا خَلُوقًا فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَا أَحْسَنَ هَذَا " .
also referenced under: Hadith 728 (Reference) & Volume 1, Book 8, Hadith 729 (DarusSalam)