Dishpan hands can't reveal your age anymore, but, alas, science is finding new telltale clues.

In experiments on rats, researchers at the University of Illinois report they have found 10 chemicals in urine that change with age. "Show us the levels of these chemicals, and we can tell you the rat's age," says Dr. James Webb, one of the scientists on the project.

If similar organic acids are found in humans, the researchers say, it may shed new light on the aging process.

Webb and other researchers told the American Chemical Society that they will next vary the diets of the rats and see if the chemical levels change. The hope is that certain diets may ultimately be found that slow the aging process.

"Some people believe that a restricted, low-calorie diet can slow the aging process," Webb told a meeting of the society in Chicago last week. "We plan to investigate this."

The researchers also plan to see if environmental chemicals have an effect on aging.

But first they have to find the telltale aging chemicals in human urine, which could be difficult. "There's considerably more genetic variation in people," Webb said, "and that complicates things."