Just had a little root about and found some blue fluff in my naval, weird as I don't have any blue shirts and when i sniffed it I noticed it was smelling bad really bad .
just wax your belly and wash every day - problem solved. obviously not speaking from experience with the whole waxing your belly thing...
What age does your belly button start stinking ? It doesn't if you wash, you uncouth, malodorous weirdo