Businesses pay the brothers to put ads on the TP—which comes from wholesalers such as Georgia-Pacific. Jordan Silverman believes their business is the only one of its kind in the U.S., and they've filed for a patent, he told CNBC.com. "Other people have thought of the idea. We've actually done it."

The brothers' toilet paper is manufactured with 100 percent recycled, environmentally-friendly materials. And the ads are printed with soybean-based ink—and non-abrasive.

Rough start

In the beginning, potentialadvertisers didn't welcome the unique business model. "I've been cursed off. I've been yelled at. I've been hung up on many times," Jordan Silverman says. But Silverman and his 19-year-old brother Bryan kept at it.

"You look forward to the 'nos' because that means the next 'yes' is just coming that much sooner," Jordan Silverman said.

Advertisers eventually signed on and the company, based in Ann Arbor, Mich., prints ads for more than 60 firms, according to Silverman. Businesses include a smoothie maker, insurance office and doctor's office.

Star Toilet Paper then offers its ad-filled TP for free to venues including libraries, restaurants, bars and bowling alleys. Venues in New York, North Carolina and Michigan feature the TP, but it's not available for sale at retailers.

As their customer base builds, the Silvermans are growing their staff and seeking investors. They hope to expand into regional sales and beyond. The company is also targeting larger venues including stadiums, airports and colleges. Offering them free TP can be a "huge savings" for them, Silverman says.

As their Twitter handle @startoiletpaper proclaims: "Don't Rush, Look Before You Flush!"

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