Next, dissolve the lye (Sodium hydroxide) crystals in water. Gear up with eye protection, gloves, and wear a long sleeved top. In an airy place, outdoors is best, pour the lye crystals into the water and stir well. There will be a lot of heat and steam so be careful. Try not to breath it in. Leave outside in a safe place, or in a shallow basin of water to cool.