Huminski, like most estheticians, has been reusing the wax for her clients for years and has never considered it a health risk.

"I just apply an antiseptic to the skin to remove all the germs and cleanse the skin beforehand," she says, "and then I apply the wax with a spatula or wax stick. Every time, I use a clean one. The wax is so hot I don't think germs or bacteria can live in there."

But they can. Pugliese explained that a problem can arise if a piece of skin, or something else from the human body, were to get into the wax, introducing an element of water. Heating the wax to the melting point would not kill the bacteria.

"The wax isn't heated to the boiling point, obviously, or you would seriously burn the skin. When you sterilize something you have to take it up to 220 degrees and hold that temperature for 15 to 20 minutes," says Pugliese.

Another concern is about bacterial spores. "If the bacteria is in spore form, you can hit it with a hammer and it can still live," he says.

So what should you do if you choose a salon waxing? Experts say to err on the side of caution.

"I would always ask for fresh wax," says Pugliese. "They'll hem and haw, but wax isn't that expensive. And if you're having more than one area waxed, remember the most bacteria will be in the bikini area, so do that last. And make sure they put a germicide on the skin before and after. That's why a lot of guys use after-shave when they get nicks. It's really just alcohol and helps with infection."

"A good high-end salon would not mind giving you a fresh batch of wax. And I would ask to see it done in front of me," says Lamas. "I come from the school that I wouldn't want someone's bikini wax on my lips even if it's boiled to death."