Musannaf Ibn Abi Shayba 1:688

688. Asbat ibn Muhammad narrated to us, from al-Shaybani, from Muharib ibn Dithar, from Ibn Umar regarding the ritual bath (ghusl) from major ritual impurity (janaba). He said: He performs his ablution (wudu) as he does for prayer, then he washes what has touched him [of the impurity]. Then he strikes his hand upon the ground and rubs it with dust, then he pours water over it.