Eyewitness News also got e-mails from people who say it happens every week before the trash trucks come around to pick them up.
"You see them on our gardening days, Tuesdays and Wednesdays, up and down the street, sometimes in trucks, sometimes on foot, sometimes on bike, and it's kind of become a business," said L.A. resident Vitoria Miller.
Chris Shaw says it's a business for him. He goes through trash cans several times a week, taking out plastic bottles and whatever else he can find. He takes everything to a recycling center and turns it in for money.
"It helps pay your rent," said Miller. "You find a lot of good things in the trash. You find cell phones, computers, laptops, dishes, clothes. It's profitable."
Profitable, sure. Legal? No.
"Scavenging is against state law and it is a misdemeanor," said Pat Proano from the L.A. County Dept. of Public Works.
Proano says taking a few bottles here, a few bottles there all adds up. It takes money out of the recycling program. It's difficult to get an exact number for how much it costs, but it affects the city's revenues.
"All the recycling, the trash haulers give you credit for all the revenues that they're generating from recycling, so that's keeping our trash rates down," said Proano.
"Some people've got to make a living. Yeah it probably belongs to the city, but I don't really consider it as stealing," said Shaw.
And it's also about security. Letters and other items in your trash could reveal some of your personal information.
Victoria Miller mostly worries about identity theft. She says she told a few people to stop going though her trash, but it didn't work.
"My husband's been putting our blue recycling can back on our property overnight before trash day, and they've actually come onto the property to dig, so we put it behind the hedge thinking we'll just wheel it out in the morning, and they're still going for it," said Miller.
If you're bothered by people scavenging, don't take it upon yourself to deal with the problem.
"We don't want residents to confront the scavengers, but rather to call local law enforcement agency, either the sheriff's department or local police department and give them a description of the vehicle, license plate if you can, and have it investigated," said Proano.