I think they are rather potent. I had one done by a salesperson, and it totally zapped my energy for a couple of days. I don't know it that was good or bad but I like the milder foot soaks. A little salt and baking soda in hot water for about 10 minutes. I remember reading that the body throws toxins to the extremeties if it can't get rid of them thru the normal elimination routes. So it makes sense to me. I also read that soaking the feet at night helps balance the meridians of your body. Maybe it's because it does pull out the heavy metals. You can also do a search for detox baths. They have some that require baking soda and Sea Salt and some that use vinegar, some that utilize Epsom Salts .