Fashion comes at a price. But who knew that it would claim our entire system of money?

Since American money was consolidated into a single system of currency in the late 1800s, U.S. dollars have been printed on a unique cotton blend paper. That paper has been supplied by a single company, Crane, for more than a century. And Crane relied on scraps of denim sold in bulk by the garment industry for its cotton.

The company bleached and processed the unwanted fabric, then rewove the fibers into the George Washingtons and Benjamins that graced our wallets. About 30 percent of Crane's cotton came from leftover denim, making it one of the largest single source of the fibers, according to Jerry Rudd, managing director of global sourcing. The rest of the cotton came from a hodgepodge of other textile wastes.

But something strange began to happen in the 1990s: Denim became tainted.

The stretchy fabric commonly known as spandex (and trademarked as Lycra) had been invented in the 1960s for use in women's lingerie. By the 1990s, the fashion world had discovered that blending it with denim created a curve-hugging -- and yet still forgiving -- fit. It never looked back.

"Everybody's into it. Denim and Lycra are all over," Rudd said. "It's just incredible what's happened to the industry."

The trend was bad news for Crane. Even a single fiber of spandex can ruin a batch of currency paper, degrading the strength of the material. But separating the spandex from the cotton would be a Herculean task, Rudd said. By the early 2000s, almost every pair of jeans contained at least a hint of stretch -- rendering them useless to Crane.

"There's no denim products out there that we can find that's basically not contaminated," Rudd said.

Crane had to adapt. Instead of using cotton from denim, the company now looks "beyond the waste stream," Rudd said, to "the natural fiber itself." In other words, they buy cotton straight from the source and leave the world of fashion to its own devices.

"It's a sign of the times," Rudd said.