Hi, thank you for your feedback ❤️. You need to Twist the neck of the roller in the direction of the arrows marked on it's neck. It will separate the neck from the body.Take out the stone and wash it under running water with soap. Assemble the roller like it was opened. Look carefully at the sequence of the assembly so it is easy for you to reassemble it afterwards. Also, it gets dark when it absorbs the oil but it will not change it's effectiveness. So don't worry about the colour.