There are all kinds of gross things in your body right now, maybe even hard lumps of calcium oxalate (that's what a kidney stone's made of). You're making sweat, and eye gunk and pus, and you also have undigested and partially digested food traveling through your gut. And did you know there are more bacteria living in your body than there are human cells? We'll get to that in a moment. First, let's talk about the mites having sex on your eyelashes.