
If your crock pot was large enough, and your feet small enough, this would work great. I have an electric foot bath that's supposed to keep the water warm, but it doesn't, so I'm sorely tempted to try this some time. An oval crock pot might work well if it's wide enough for both your feet.
Slow Cooker Potpourri
2 tsp cinnamon
1 orange peel (I also had part of a dying half orange and tossed it in)
3 whole cloves
1-2 cups warm water
Cover with lid slightly ajar and turn on high. Add water as necessary.
Here is a more complex recipe. I think the oil might slow down the evaporation, but it might also enhance the aromas, helping to volatilize the oil-soluble compounds in the spices.
Home Made Air Freshener
1 1/2 cups warm water
4 cinnamon sticks broken into pieces
1 tsp. imitation vanilla
1 tsp. nutmeg
1 tsp. ginger
1/2 tsp. almond extract
1/2 tsp. allspice
1 1/2 tsp. vegetable oil
Place the ingredients into a crock pot and mix together. Let simmer. Be careful to watch the crock pot, and add additional water as needed, as the heat will cause the water to evaporate.
You can find an electric potpourri pot or get one of those small crock pots that are intended for hot dips. Mine little one came free with my big (foot bath size) crock pot.
Here is one from Paula Deen:
Sliced apples
Sliced lemons
Sliced oranges
Water
Bay leaves
Whole cloves
Cinnamon sticks
In a slow-cooker, combine fruit to preferences of smell. Cover in water. Top with bay leaves, whole cloves, and cinnamon sticks. Leave slow-cooker on low.