There is a school of thought that believes mold can be a frequent culprit of chronic sinusitis. There are a few different types of fungal sinusitis but the one that appears to be the most common is called EFRS (eosinophilic fungal rhinosinusitis). This was shown in a Mayo clinic study in 1999. It's important to note that it is really an allergic reaction to the mold rather than an infection caused by the presence of the mold. In the Mayo clinic study, the 'normal' people had just as much mold as the 'sick' people. The sick people were sick because their immune system mounted an allergic reaction to the mold.
Using an anti-fungal nasal rinse would be one step to dealing with this. Other steps may include allergy tests and treatments. One of the main weapons would be to find and reduce your exposure to mold. I would think that normal sinus rinses would have some benefit in washing away mold, but I would try to see a doctor who will properly evaluate you and write you a prescription for an anti-fungal rinse.
Hope this helps...
You may want to try a prescription nasal spray with an anti-fungal in it (itraconazole or fluconazole usually do the trick) These kill fungus trapped in the sinus