It's one of the hottest spa treatments around. A foot bath that some spas claim can actually remove toxins from your body right through your feet.
But we were curious. So INSIDE EDITION visited several spas in New York City and brought along a hidden camera as they performed the treatment on INSIDE EDITION'S Lisa Guerrero.
At every spa visited, we were told the device can improve your health and that the color change in the water was the result of toxins being released from the body.
The treatment is simple -- you put your feet in warm salt water for 30 minutes with an electronic device spas call an array. Almost immediately, the water starts turning brown. After the end of the procedure, the water is dark brown and filled with metal flakes. Many spas then consult a chart to determine which organs have been detoxed based on the color of the water.
At the Antoinette Boudoir Spa in the heart of Times Square in New York City, the water turned brownish-orange.
"The orange color comes from liver and joints," an employee at the spa told Guerrero.
The employee and the spa's owner, Clara Raykin, said the device can help patrons with headaches and sleeplessness.
At the La Casa Day Spa in midtown Manhattan, we had a similar experience. Once again, the water turned brown and metal flakes appeared.
An employee at La Casa told Guerrero the metal flakes came out of pores in her feet and also analyzed the water to determine what parts of the body had been detoxed.
"Joints and arteries," the employee said after consulting her chart.
But Dr. Stephen Barrett, M.D. told INSIDE EDITION that the device cannot possibly draw toxins through the feet.
So we bought our own foot bath unit and had it tested by Steven Fowler, an electrical engineer.
Fowler tested the device in his lab in South Carolina and quickly discovered what's changing the water color. "Everything you see here is just rust," Fowler said, gesturing to a tub of the brown water.
Fowler said inside the "array" that is placed in the water are just two metal electrodes with a positive and negative current. When introduced to salt water, a chemical process called electrolysis takes place and causes the electrodes to rust at an extremely rapid rate.
"This is nothing more than two pieces of metal rusting," Fowler said. "This has nothing to do with toxins. It is just a simple chemistry experiment."
Fowler even tested the device for us without feet in the water and not surprisingly, the water still turned brown.
"It is nothing but a scam," Fowler said.
Armed with this information, Guerrero went back to the spas to share with their owners what our research uncovered.
Raykin, of the Antoinette Boudoir spa invited us and our cameras into her spa to prove the device worked. To test it, she ran two baths for us, one with feet and one without – a test she admitted she had never tried before.
Within just two minutes, the water started changing color.
Guerrero said, "There's no feet in this tub and already the water is starting to turn color."
"No, no," Raykin said in disbelief.
Raykin insisted the water in the empty tub would remain clear. But when the 30 minute treatment finished, the evidence was overwhelming. Both tubs were filled with the same dark-brown rusty water.
Guerrero asked, "Clara, how do you explain that both of these tubs have dirty rust-colored water with particles in them, when somebody's feet were in this one and nobody's feet were in that one?"
"I cannot really explain it," Raykin responded.
Finally, Raykin admitted the device does not detox organs.
"Clearly it doesn't work," Guerrero said.
"Actually, it looks like you're right," agreed Clara.
The owner of the La Casa Day Spa, Dr. Jane Goldberg, Ph.D., did not return our calls requesting an interview, so Guerrero caught up with her on the street as she was leaving work.
"There's scientific documentation for it," Goldberg said.
"That's not true is it?" asked Guerrero. "It's a scam. You're charging people $60 for a scam. It's like snake oil."
"Science is science," Goldberg responded.
"Science proves that this doesn't work," said Guerrero.
Nonetheless, both Goldberg and Raykin said they were still going to offer the service to customers.
So it seems that as long as people are willing to pay good money to soak their feet in nothing but rusty salt water, there will be businesses to accommodate them.
That spa owner says she is going to send us scientific studies from the manufacturer of the foot bath she uses. By the way - the one we purchased has a disclaimer on the bottom that says it should not be used to diagnose or treat medical conditions.