Floss every day. That’s what your dentist tells you, but what she (or more rarely, lately, he, because there are fewer men engaging in the profession than ever before) doesn’t say is how to dispose of the used floss. Not in the toilet, according to a the people who manage Toronto’s sewage treatment. It lodges in the equipment, causing breakdowns and crashing the system. So be a good citizen, floss every day, and then drop it into the garbage can. By the way, the image is a photo of graffiti featuring floss, in, where else? – Brazil. (Notice: This is not a paid ad.)