Ata' bin Yasar says: Sayyiduna Ibn Abbas (may Allah be pleased with them both) said to us: Would you like me to tell you how the Messenger of Allah (peace and blessings be upon him) used to perform ablution? Then he narrated the long hadith, saying: Then he took another handful of water and sprinkled it on his foot while the sandal was on it, did the same with the left foot, and wiped under the sandals.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 341