The Collaborative International Dictionary of English v.0.48:

Abstersion \Ab*ster"sion\, n. [F. abstersion. See Absterge.]
   Act of wiping clean; a cleansing; a purging.
   [1913 Webster]

         The task of ablution and abstersion being performed.
                                                  --Sir W.
                                                  Scott.
   [1913 Webster]