WASHINGTON -- These days Ben Cohen, co-founder and former CEO of Ben & Jerry's, is trying to make an impact with stamps, not scoops. His target: the inordinate influence that money and those who possess large amounts of it have over politics.

The Stamp Stampede sells rubber stamps that let users impress a variety of phrases -- "Get Money Out Of Politics" or "Not To Be Used For Bribing Politicians" -- on paper money. The idea is to take advantage of how dollar bills move: As they pass from hand to hand, so will the message.

"Money moves virally around the country," Cohen said. "Viral marketing only got to be hip and new and in since the Internet, but there are other things that spread virally."

The onetime ice cream mogul, who is no longer affiliated with the company he helped found, is pushing hard this election year to expand his Stamp Stampede. According to its website, the campaign, which launched in 2012, has already sold more than 12,000 stamps across the country. Businesses are marking money at their registers and recipients of stamped bills are spreading the message via Instagram.

Long a champion of progressive political causes, including reducing the size of the defense budget, Cohen was drawn to the issue of money in politics by the 2011 Occupy Wall Street movement and its protest of economic inequalities. As more and more issues began to crowd the movement's initial focus, Cohen said, "I felt like there was a real need to focus and I felt like the one thing that was in common to most of those things was money in politics."

Cohen decided that what he could bring to the fight was a tool for the ordinary person who is upset about the influence of money in politics.

"There were all these millions of sympathizers in the country, but virtually none of them were ever going to occupy a park or go to a demonstration or whatever. But there needed to be some kind of visual way for them to show their support, and I came up with this idea of stamping money as a way of showing support," Cohen said.

Political activists have put slogans on money before. During the push for women's suffrage in the United Kingdom, suffragists carved "Votes for Women" into the one-penny coin atop the face of the king.

The Stamp Stampede website seeks to alleviate any fears people might have about the possible illegality of stamping messages on money. It posts a lawyer's opinion explaining why being convicted for defacing the bills is unlikely. As the website notes, the Stamp Stampede's intent is not to make the bills illegible and unusable; it wants them to stay in circulation.

To advance his Stamp Stampede, Cohen has been meeting with a wide range of organizations working on the money-in-politics issue, including People for the American Way, Greenpeace, the Sierra Club, Public Campaign, the Communications Workers of America and more. He offers these groups the opportunity to have their website URL engraved on one of his stamps.

These groups embrace diverse solutions to money's influence: Some support a constitutional amendment to "get money out of politics," while others aim to pass legislation to expand public financing for campaigns. But Cohen is not picking and choosing among those ideas.

"We're in favor of all that stuff," Cohen said. "We are, like, the person on the street who just wants to get money out of politics, and they don't really care if it's done by an amendment or by legislation."

The push to promote the Stamp Stampede is heading to familiar grounds this year for the Ben & Jerry's co-founder: spring and summer music festivals. Cohen's connection to musicians has already helped him land some big-name endorsers, including David Crosby, Jackson Browne, the late Pete Seeger and Zydeco musician Terrance Simien, who mentioned the Stamp Stampede upon accepting a Grammy during this year's nontelevised portion of the awards ceremony.

The artist Shepard Fairey is also working on a piece on a sheet of Treasury bills to help promote the campaign.