Bring a large pot of water to a boil, and add in rosemary. Allow to boil 5 minutes, so the rosemary infuses into the water. Remove from heat. 

In a large container big enough to fit your feet into, layer sliced lemons onto the bottom, then sprinkle in epsom salt and baking soda. Pour in hot water with rosemary, and allow to cool enough to where you can put your feet into the container without burning them.

Soak feet in the mixture for 15 – 30 minutes.