When Calli stuck a bead up her nose a couple weeks ago, people started telling me horror stories about how they know someone who stuck something up their nose as a child and no one knew it until they got super terrible stinky breath from something rotting up there.
I also think that one of the viruses that's going around right now has bad breath as a precurser. I have encountered several people at work in the past few weeks with the same kind of bad breath and almost all of them eventually came down with the crud.