This is a video on how to dissect a dry cell and get its parts (Carbon rod, zinc can, MnO2/C powder) without damage so they can be used in other experiments.
(i) Carbon rod : Mainly used as electrodes on electrolysis and simple cell, spark gap etc.
(ii) Zinc : Used to make a simple cell, produce hydrogen ,making various zinc salts etc.
(iii) Manganese dioxide : As a chemical reagent for many chemical reactions (like preparation of chlorine)

!!! Open up the cells as soon as they are dead otherwise the MnO2/C starts to become stiff by drying and the carbon rod breaks during recovery !!!