When my daughter was little, she developed a random fear of cigarette butts on the ground. She'd freak out every time she saw one, and usually demanded to be carried across parking lots. We tried helping her get over the fear by explaining that cigarettes are gross, yes, but they won't hurt her. My son explained to her that when she saw one, she should stomp on it or kick it to prove she wasn't afraid. It worked, but... she had the following conversation with my mother a while later:
Emma: Nana, I hate butts! They're dirty and smelly!
Mom: They are.
Emma: You know what I'm gonna do when I see one?
Mom: What?
Emma: Kick it!