This old man is truly worthless, irreparable, unchangeable, incorrigible, and incurable. The way God deals with the old man is to crucify him. God wants to give us something new. The old man has to die. God's words charge us to wash away all of our sins in the precious blood of the Lord Jesus.
"The blood of Jesus His Son cleanses us from all sin."
"Who loves us and has loosed us from our sins by His blood."
The sins here refer to the acts of sins committed by a person outwardly. The Bible never tells us that the old man within is to be washed. God's word never says that the old man should be washed. (The blood of Jesus Christ washes our sins, not the old man.) The old man needs to be crucified. This is the word of the Bible.