Wood ashes are common source of potassium compounds e.g. potassium carbonate, that can be easily separated from other combounds by leaching with water followed by filtration and evaporation of the solution. In this wideo I showed the process of extraction potassium compounds from wood ash and then transformation into potassium chloride.

0:00 intro
0:57 extration of potassium compounds from wood ash
2:37 making potassium chloride from wood ash extract