"Sanctions? Don't make my Iskanders laugh," reads one T-shirt, referring to a Russian missile system. "The Topol is not afraid of sanctions," says another, vaunting the power of a Russian intercontinental ballistic missile.
A bus, decorated with the blue, white and red of the Russian flag, has already exchanged 10,000 tops this week and is due to keep on touring the capital until October 6.
"Everyone's been responding well, even foreigners. People are giving up their shirts with pleasure," said Anastasia Zadorina, the campaign's designer, wearing one of her own creations -- "We have our own cool things without Coca-Cola."
Western nations have imposed an array of sanctions on Russia in response to its involvement in the conflict in Ukraine, including its annexation of Crimea earlier this year.
The punitive measures have limited Russia's access to foreign money, sent the rouble to historic lows and slowed economic growth to a crawl. Russia has responded by banning many Western food products and appealing to patriot fervour.
"We can live without oysters and Parmesan and without Western fashion," Zadorina said. "We don't want to offend anyone, we just love our homeland."
Although Russia is becoming increasingly isolated, President Vladimir Putin has won backing at home, with a survey by the independent Levada pollster putting support for him at 86 percent in September - the highest since 2008.
Some of the T-shirts on offer were printed with pictures of military hardware, while others are decorated with an image of the knotted red necktie, synonymous with the Communist Pioneer movement of the former Soviet Union.
The self-styled "ideologist" behind the campaign, Ksenia Melnikova, said the project was not funded by the Kremlin. The group's website lists Moscow's Vnukovo airport and two other Russian firms as corporate partners.
"We're going to Crimea 100 percent. Other regions are inviting us also," said Melnikova. The Western shirts will be recycled or used to make a political artwork, she added.
Oksana, a 25-year-old student, said she was happy "to support this patriotic campaign" and swap in her Western top for a new Russian design.
"It will all be okay in the end though, we'll be friends again with the West before long," she said.
