How To Remove Musty Smell In Nasal Cavity?

I am conscious of a musty smell in my nasal passages. I have had sinus infection in the right lower sinus that was treated with medicated nasal wash and cleared up the infection. this was a few months ago. The constant musty smell started about a week ago. I am on clarithromycin and prednisone for a possible sinus infection in upper cavities but smell persists.