Use 1 cup of Epsom salt, sea salt, or table salt for a standard-size bathtub. Pour the salt into the warm running bath water and use your hand to stir the water to help dissolve all the grains. Soak in the tub for at least 20 minutes. This is the highly recommended and most effective way to use shower salts and enjoy their full potential and benefits. For further instruction, you can consult the product description section on the website or look at the details on the printed manual that comes in the packing of the soap.