Just thought I would also put the recipe I have in here, the ingredients are slightly different.
Pastilles SCENTED STONES
1/2 cup flour (do not use self-rising flour)
1/4 teaspoon powdered alum
2/3 cup boiling water
1/4 cup salt
1 tablespoon essential oil
1 glass or ceramic bowl
1. In glass or ceramic bowl thoroughly mix all dry ingredients
2. Add essential oil and boiling water to dry ingredients. Scent will be strong, but will fade slightly when pastilles dry.
3. For colored dough, blend in food coloring one drop at a time until desired shade is achieved.
4. Blend ingredients to form a ball.
5. Working with a small amount at a time (approx.1/8 teaspoon) roll dough between palms of hands to form small balls (cover unused dough to keep moist)
6. Allow pastilles to dry.
It is very important that you use the alum. This is what helps take out the moisture to allow them to dry better
Hopes this helps.