Add the baking soda, and Epsom salts to a mixing bowl.
Then add the water and eucalyptus leaves, and stir.
Carefully add the essential oils to the bowl, and stir well.
Using a spoon, add the mixture to the mould cavities. Gently press down with the back of the spoon to pack it down very well.
Let set in a dry place for 24-48 hours.
Take the melts out of the mould and store in an airtight container.
To use: Place one mould at the corner of the shower, allowing the steamer to get wet. As it melts, it will release the essential oil vapours. Do not keep in a direct water stream.