Mix your bircabonate of soda, tartar, oil, essential oils and food colouring until you have a colour you are happy with
2-3 sprays of water
It will start to sizzle as the bicarbonate of soda reacts with the water. Start mixing it and it will feel a little more “solid”, a bit like wet sand. When you can indent your spoon on the mixture and leave a nice “shape” behind without it crumbling too much you are ready to transfer to your ice cube trays
Using a SPRAY bottle really is important (use a cleaned out cleaning bottle), as this disperses the water evenly and avoids, the bircab to just sizzle away in one part of your bowl
Mix in some lavender
Fill into your icecube trays (silicon REALLY IS BEST, else it is VERY HARD to get out in one go) and press down hard
Let dry for at least 1-2 days. They get harder over time - the longer you leave them the better
Remove gently and done. If you find, they break apart, you didn’t add enough water spray to begin with. You can crumble it all again, spray with more water and start again