Sayyiduna Anas (may Allah be pleased with him) says: I saw the Prophet (peace and blessings be upon him) spit into his garment during prayer and then rub it with his fingers.
Al-Tabarani recorded it in al-Mu'jam al-Awsat, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2007