DIY Gifts : Good Ideas For You | DIY Lime Mint Foot Soak - DIY Refashion To make the foot soak, combine 2 cups of Epsom salts with 1/2 cup baking soda and zest of one lime in a large bowl, and add 3-4 drops of lime essential oil and 3-4 drops of peppermint essential oil. Stir with wooden spoon to mix thoroughly. (optional, you could add just a drop of green food coloring if you’d like) Pour the mixture into a jar or bag, and use within a few weeks.