Windsor, Ont., has a new weapon in the battle to keep its streets clean: portable ashtrays.

They're plastic, the size of a dental floss dispenser with a snap-shut lid, and they are free.

They're also flame retardant, meaning smokers can stub out their butt in the tiny boxes and throw them into the next garbage can they come across.

"You can spend an hour just cleaning up cigarette butts and still it doesn't look like you've accomplished a lot because there are so many of them," Janice Dama, Windsor's clean city co-ordinator, told CBC News.

 "They're lightweight, they get in the crevices, they'll blow around, you know, they travel. They're one of the hardest things to collect."

There are also lots and lots of them. Thousands of smokers toss their butts onto the street, where they blow around and accumulate in the gutters and grass.

Now, Windsor has joined an international campaign to eliminate butts by handing out portable ashtrays at a downtown intersection.

The ashtrays are used extensively in Australia, where they're manufactured. They're also being used in England, Israel, Malta, South Africa and the United States.

At least one Windsor smoker says he'll use the ashtray, at least when he's downtown.

"It does look bad a lot of the times, with all of the cigarette butts and stuff like that," Bob Cowan said.  "I'll use it when I'm downtown, anyway."