"Vicks" vapor shower pucks

We made these in mini muffin tins. This recipe made 12 pucks
We combine 1 cup of baking soda and 1/3 cup of water. We filled 12 mini muffin cups.
It was baked for 20 minutes at 350.  
After the "puck" is cool THEN add a few drops of each essential oils (eucalyptus, rosemary, peppermint, and lavender).

This recipe was found at
http://beingfrugalbychoice.blogspot.it/2012/03/homemade-vicks-vapor-shower-disks.html

We added peppermint essential oil, it has such healing properties.