It was narrated from Anas that the Prophet (Peace be upon him 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 ﷺ أَخَذَ طَرَفَ رِدَائِهِ فَبَصَقَ فِيهِ فَرَدَّ بَعْضَهُ عَلَى بَعْضٍ .