If you are looking for a natural treatment for sinusitis and congestion, you can try using apple cider vinegar in two ways, ingestion or inhalation.
You can drink 1 teaspoon of apple cider vinegar three times a day. Or, if you have a hard time taking it pure, drink a mixture of two tablespoons of apple cider vinegar, 1 tablespoon of honey and 8 ounces of water.
You can also mix together equal parts of water and apple cider vinegar, heat it, and inhale the steam through your mouth. It is said that this steam method can also help to kill bacteria.