• Directions- For general soaking to ease minor aches and pains add 2 cups of Epsom salt to your warm (not hot) bathtub. Soak for up to 20 minutes. • For minor sprains - add 1 cup of Epsom salt to about a gallon of warm water. Soak for 30 to 45 minutes. • For exfoliating - after soaking your desired body part, massage a handful of Epsom salt into your skin.