(33) باب حَكِّ الْبُزَاقِ بِالْيَدِ مِنَ الْمَسْجِدِ
Narrated `Aisha:
(the mother of faithful believers) Allah's Messenger (ﷺ) saw some nasal secretions, expectoration or sputum on the wall of the mosque in the direction of the Qibla and scraped it off.
Reference: Sahih al-Bukhari 407
In-book reference: Book 8, Hadith 59
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 8, Hadith 401