Source : Webster's Revised Unabridged Dictionary (1913)

Decalcify \De*cal"ci*fy\, v. t. [imp. & p. p. {Decalcified}; p.
   pr. & vb. n. {Decalcifying}.]
   To deprive of calcareous matter; thus, to decalcify bones is
   to remove the stony part, and leave only the gelatin.

Source : WordNet®

decalcify
     v 1: lose calcium or calcium compounds
     2: remove calcium or lime from; "decalcify the rock" [ant: {calcify}]
     [also: {decalcified}]