Walk down a street in Montreal, and there's a good chance you'll see cigarette butts lying on the ground.

The city says those butts make up about 30 per cent of the litter on our streets.

A new campaign is encouraging smokers to pick up after themselves, so that the city doesn't have to foot the cleanup bill for the butts they leave behind.

"We're spending $40 million a year to clean up the city, for the whole year," said city spokesperson Philippe Sabourin.

"So imagine, if one third of the litter doesn't have to be grabbed — the taxpayer could save a lot of money here."

The city put out a call on social media this week, calling out "buttheads" who toss their cigarette butts on the ground instead of throwing them out in designated containers.

Cigarette butts represent 30% of the waste the city picks up. Their toxic residue poisons our environment.<br><br>What do you do when you see someone being "buttheaded"? <a href="https://t.co/Tnpoj124XH">pic.twitter.com/Tnpoj124XH</a> —@MTL_Zoom

Since 2016, more than 600 of these public ashtrays have popped up around the city.

The butts are collected, and then recycled as part of the Mégot Zéro (Zero Butts) program, started by a local environmental non-profit.

Vincens Côté, director of the Society for Environmental Action, Education and Sensitization (SAESEM), told CBC News that the initiative is about more than just making the streets look cleaner.

Vincens Côté is the director of the Society for Environmental Action, Education and Sensitization, known by its French acronym, SAESEM. (CBC)

"There are several hundred different types of toxic substances in those cigarette butts. And when they're put on the ground, they eventually leach into the groundwater and the rivers," he said.

This year, the city will expand its urban ashtray program, adding more than 200 across the island.

The city intends to install the new containers by July.