polishing slate

from The Collaborative International Dictionary of English v.0.48

Polishing \Pol"ish*ing\,
   a. & n. from {Polish}.
   [1913 Webster]

   {Polishing iron}, an iron burnisher; esp., a small smoothing
      iron used in laundries.

   {Polishing slate}.
   (a) A gray or yellow slate, found in Bohemia and Auvergne,
       and used for polishing glass, marble, and metals.
   (b) A kind of hone or whetstone; hone slate.

   {Polishing snake}, a tool used in cleaning lithographic
      stones.

   {Polishing wheel}, a wheel or disk coated with, or composed
      of, abrading material, for polishing a surface.
      [1913 Webster]