Pour the kosher salt in with espom salt and baking soda.
Mix the three ingredients together throughly.
Add red food coloring to the salts and mix in (I had to press down on the lumps that formed around the drops of food coloring to get them to mix in) - keep adding food coloring until you have the desired color (I was going for a light pink, not red, so I only used approx. 12 drops)
Add the essential oil and mix throughly.
Use a funnel and spoon the balt salts into the funnel on top of a jar.