you'll probably need to consult a doctor first before you proceed with these nasal flushes. Probably its just a case of post-nasal drip in which case sinus irrigation would help.
But if you're a BO sufferer, then let me tell you that this smell wouldnt dis-appear as its one of the ways the body releases out toxins. Skin, hair, nose, feet are the most common areas. I get the smell too all the time, especially when you're in crowded areas. Its as if you're surrounded by garbage, when actually i'm the one releasing it. Hmm :)