This Bible contradiction is from the Skeptic's Annotated Bible.
By spitting on his eyes.
Mark 8:22-25 View context
And he cometh to Bethsaida; and they bring a blind man unto him, and besought him to touch him.
And he took the blind man by the hand, and led him out of the town; and when he had spit on his eyes, and put his hands upon him, he asked him if he saw ought.
And he looked up, and said, I see men as trees, walking.
After that he put [his] hands again upon his eyes, and made him look up: and he was restored, and saw every man clearly.
By spitting on the ground, wiping the muddy spit on his eyes, and then washing it off.
John 9:1-6 View context
And as [Jesus] passed by, he saw a man which was blind from [his] birth.
And his disciples asked him, saying, Master, who did sin, this man, or his parents, that he was born blind?
Jesus answered, Neither hath this man sinned, nor his parents: but that the works of God should be made manifest in him.
I must work the works of him that sent me, while it is day: the night cometh, when no man can work.
As long as I am in the world, I am the light of the world.
When he had thus spoken, he spat on the ground, and made clay of the spittle, and he anointed the eyes of the blind man with the clay,