Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: The Messenger of Allah (peace and blessings be upon him) was shrouded in a garment that he (peace and blessings be upon him) used to wear and in a shirt. Al-Fadl (may Allah be pleased with him) and a man from the Ansar washed him (peace and blessings be upon him); the Ansari kept pouring water over them and washing beneath the cloth. He (peace and blessings be upon him) was washed while wearing a shirt, which was not removed until the washing was complete.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12095