Sunan an-Nasa'i, Book 1, Hadith 310 (In-Book) ⓘ
It was narrated from Anas that the Prophet (ﷺ took the hem of his garment and spat on it, rubbed it together briefly and let it drop.
أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، قَالَ حَدَّثَنَا إِسْمَاعِيلُ، عَنْ حُمَيْدٍ، عَنْ أَنَسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم أَخَذَ طَرَفَ رِدَائِهِ فَبَصَقَ فِيهِ فَرَدَّ بَعْضَهُ عَلَى بَعْضٍ .
also referenced under: Volume 1, Book 1, Hadith 309 (DarusSalam)