Yeah Amber, when you have a butt to put out, it is still "lit" on the end, still burning. When you put a butt out, it's best to put it flat on a surface so that the fire is smothered out. When a small car ashtray is full, and you are driving, a smoker may try to just push the still lit butt into the middle of a bunch of dead butts, instead of pressing it against the sides of the ashtray to smother the fire. When a person does this, pushing a lit butt onto a dead butt filter, well of course it only lights that filter on fire. So instead of putting a fire out, you've passed the fire along from butt to butt. And it's not really a fire, per se, just a LOT of smoke. Will fill the interior of your car up in seconds with it's lovely smell LOL. It's more of an annoyance than a danger, but still...
