Salt lowers the freezing point of water making it possible to achieve below freezing temperature when applied to ice. Any type of salt, including table salt, may be used for this purpose. Since the salt will eventually melt the ice, coarse salt would be preferred because it dissolves more slowly. Rock or solar water softening salt tends to be coarse and will work well for this purpose. Pellets and Sun Gems® are too coarse and should not be used.
