It can't be due to uncleanliness as the law ended when he died. So why does he say:
John 20:17
Jesus saith unto her, Touch me not; for I am not yet ascended to my Father: but go to my brethren, and say unto them, I ascend unto my Father, and your Father; and to my God, and your God.
http://www.scripture4all.org/OnlineInterlinear/NTpdf/joh20.pdf