The Collaborative International Dictionary of English v.0.48:

Unshale \Un*shale"\, v. t. [1st pref. un- + shale.]
   To strip the shale, or husk, from; to uncover. [Obs.]
   [1913 Webster]

         I will not unshale the jest before it be ripe.
                                                  --Marston.
   [1913 Webster]