Open one box of tamarind pods. Crack the shells and place all the flesh into a bowl. In a pot, heat up some water to a simmer. Pour the hot water over the tamarind only about half way up. Add 1/3 cup of brown sugar and a pinch of salt. Stir this mixture every few minutes for the course of an hour. Pour the mixture into a mesh strainer over a bowl to collect the water and press the tamarind pulp through the strainer to remove the strings and seeds. Pour the tamarind water and pulp into a blender and blend smooth. To a cup with ice, add a few spoonfuls of the tamarind mixture, a squeeze of lime, and fill with soda water. Stir well and serve! Refreshing!