Watch the pH drop using acid/ alkali indicator sticks and when all precipitation has occurred and the pH has reached 2 - 3, filter the crystals using a coffee filter paper, wash out remaining sodium chloride and dry the filter paper in the sun. The crystalline form when fully dry can be pressed into a 5gm or 10gm tablet and packaged away in a sealed container for possible future use.
Fig 13.4: Pressed 2.5gm & 5gm tablets of crystalline Nembutal for storage.