It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that "He wiped over his leather socks (khuffs)."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Yahya bin Sa'id (may Allah have mercy on him) except Isma'il bin Thabit (may Allah have mercy on him), and none from Isma'il except Yahya al-Jari (may Allah have mercy on him), while Ahmad bin Salih (may Allah have mercy on him) is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الألف / 1904
Hadith Takhrij«أخرجه البزار فى «مسنده» برقم: 6207»