Since I am using this salt my girl never complains about itchiness and she can play hour with the dough without having dry hands. You can buy Epsom salt in the beauty aisle of any supermarket and it does not cost more than regular salt. Epsom salt has larger grain so I always dissolve it into the boiling water before adding to the dry ingredients. We also tested lots of different oil to make this playdough. And the best oil was canola oil for it is low odour and low price and the dough was really smooth with this oil.
To make swirl in the dough I always prepare a light colour base – here is yellow. Then I divide the dough in 3 or 4 balls. I flatten each balls with my hand and add 2-3 drops of food colouring on each balls. Mix with your hands roughly and the colour will spread and makes lovely swirl. If you like add some glitter at this stage.