SEOUL, South Korea >> Some send up plastic leaflets that weigh less than a feather and flutter down from the clouds with calls for democracy or blurry cartoons ridiculing North Korea’s ruler. Some send flash drives loaded with South Korean soap operas, or mini-documentaries about the vast wealth of Southern corporations, or crisp new U.S. dollar bills. One occasionally sends his empty food wrappers, stained labels showing noodles slathered in meat sauce, so Northerners can see the good life they’d find in the South.

They are self-proclaimed soldiers in a quiet war with North Korea, a disparate and colorful collection of activists taking on one of the world’s most isolated nations — mostly using homemade hot-air balloons.

To their critics in South Korea, they run quixotic and perhaps pointless campaigns. Some are scorned as little more than attention-hungry cranks who spend much of their time exchanging insults with the others.

But the activists look across the border and see a country they believe they are already reshaping.

“The quickest way to bring down the regime is to change people’s minds,” said Park Sang Hak, a refugee from the North who now runs the group Fighters for a Free North Korea from a small Seoul office, sending tens of thousands of plastic fliers across the border every year. Fearing retaliation by Pyongyang, he goes nowhere without police bodyguards. “People are already wondering about their lives there,” he said, with the spread of outside information letting them know that life is easier in China and South Korea.

Much of what the activists send — satirical cartoons, or teary soap operas awash in lost loves, curses and amnesia — doesn’t look dangerous at all. But scholars and North Korean refugees say the outside information has helped bring a wealth of changes, from new slang to changing fashions to increasing demand for consumer goods in the expanding market economy.

While the activists often disagree about what should be sent into the North — some believe in snarky cartoons, others in documentaries, others in dry political leaflets laying out the lies of Pyongyang’s propaganda — all see themselves as warriors nudging along change.

“North Korea keeps control by blocking outside information,” said Lee Min Bok, a North Korean who was swayed to flee his homeland when he stumbled across earlier generations of leaflets 30 years ago. He has spent nearly 15 years sending leaflets into the North. “To destroy it peacefully, the influx of information is necessary.”

Pyongyang detests the activists, decrying outside influences as a “yellow wind,” even as it sends thousands of its own leaflets south every year.

“They are always trying to drop these pamphlets on us, near the border,” said Kim Song Hui, a guide at the Class Education Center, a museum of anti-American and anti-Japanese propaganda in North Korea’s capital. “But people in villages know that they should hand them in” to security officials.

How much influence do the activists have? It’s not clear, especially since some smugglers have been bringing South Korean TV shows and American movies into the North to sell for years, without the activists’ support.

“The influx of external information doesn’t shake the regime,” said Cheong Seong-Chang, an analyst at South Korea’s Sejong Institute. It may bring incremental change, by encouraging a few people to defect, for example, but he doubts it’ll do much more.

There are also risks to the balloon campaigns. North Koreans caught carrying political leaflets or flash drives could be severely punished, and the balloon launches could throw a wrench into cross-border diplomacy. The South Korean government stopped sending balloons over the border years ago, partly as an attempt to decrease tensions. The South’s new liberal president, Moon Jae-in, has reached out to the North since his election earlier this year, and a government spokesman told reporters recently that the leaflets “could spark unnecessary military tensions, including a possible accidental conflict.” Even some activists have curtailed their activities in recent years, with North Korea using specialized software to make it harder to share videos on mobile phones and other devices.

Still, every year the activists send hundreds of thousands of leaflets across the border, and thousands of DVDs and thumb drives loaded with everything from Bibles to American sitcoms to South Korean historical dramas.

Some are transported by hired smugglers via China. Some are sealed inside 2-liter water bottles tossed into the surf along the South Korean coast, then carried north by the current.

But most are carried by homemade balloons thousands of feet above the belt of razor wire and minefields that separate the two Koreas. If the winds behave, the balloons, typically about 3 feet wide and 25 feet long and made of thin translucent plastic, carry bundles of thousands of palm-sized leaflets over a country where almost no one has internet access or international phone service. Simple timers open the bundles after a set number of hours, scattering the leaflets.

The balloonists are deeply competitive and many openly detest one another (“They’re all frauds,” Lee says of the others; “North Korea is threatening only me!” insists Park).

Lee’s leaflets are slightly larger than playing cards, with messages printed on both sides in small letters. They reveal some of the falsehoods of the ruling family’s mythology, decry the authoritarianism of leader Kim Jong Un and describe the affluence of South Korean life.

But Lee, one of about four dozen activist-balloonists in South Korea, sees himself as the real propaganda, and includes personal details to make himself more credible.

“I want them to believe I was one of them,” he said in his makeshift office, a room fashioned from a shipping container that has a bed and a kitchenette. His main living space — more shipping containers where he lives with his wife and three children — are stacked above the office, in a small town about 40 kilometers (25 miles) north of Seoul.

“I put down my name, my email address, my phone number,” he said, offering a cup of instant coffee. “I tell them my place of birth and what I did” in the North.

He sometimes includes other things: flash drives with anti-Pyongyang documentaries, food wrappers, a Korean-language newspaper from Britain. Anything he believes will open a few eyes.

He knows he’s not going to start a revolution. But that’s fine with him.

“Maybe one person rebels” after reading the leaflets, he said. “Maybe one person defects. I want them to decide for themselves what to do.”