San Francisco police say 91 weapons were taken off the street in a gun buyback event in which guns were bought with cash from medical marijuana dispensaries.
Police Officer Grace Gatpandan said the haul included three assault rifles, including an AR¡15 military style rifle worth thousands of dollars that was bought back for $200.
The San Francisco Chronicle reports police, pot clubs and community groups formed an unusual partnership to organize the event.
Three of the city's two dozen medical marijuana dispensaries donated $50,000 to underwrite the buyback.
Any money not spent on the weapons would go toward funding after-school jobs and helping the families of violent crime victims.