Chop the soap into small chunks, around 2cm square. Place in a microwavable container or the inner pot of the double saucepan.
Melt the base in a microwave for about 3 minutes, 1 minute high, then low in 30 second blasts until melted throughout.
In a double saucepan simply simmer until it's melted.
This step can get messy, so ensure you have a protective covering on your work-space.
Mix the pink clay with a little water. This helps the clay disperse better in the soap base and avoids speckling!
For a more textured look, add the clay directly to the melted soap.
Now, while you are mixing, add in the essential oil.
Repeat step 3 with white clay, keeping each clay colour in a separate container.
Cut two small rectangles from sturdy cardboard, and place into a soap loaf mould, holding securely to create a seal. Pour the pink base into the middle section and white into the other two sections.
Remove the dividers, and gently swirl the colours together for a short time.
Allow the soap loaf the set overnight. When set, slice into the desired size.