Look out, this step can get smelly, so make sure you work in a well ventilated area!Place the pot over the stove, and boil it on medium heat for about 30-60 minutes.As the liquid reduces you'll start to see crystals form on the walls of the pan. Once the liquid has reduced down to about 25% of the initial amount, look out for a thin layer of film over the surface. Once you see the film, turn off the heat. Transfer the liquid to a clean jar, leaving the crystals behind. Your solution will probably be a light yellow color.