Eliminate meat, dairy products, white flour foods, and sugar. Decongestants also increase blood pressure. Helpful herbs to reduce sinus congestion would include comfrey, slippery elm, fenugreek, mullein, aloe vera, yerba santa, red clover, and white oak bark. Garlic contains a chemical which makes mucous less sticky. Horseradish has it also.
Cayenne acts in a somewhat similar manner.
Peppermint tea also helps open up the sinus passageways. Cool and gradually drink. This will help clean out the sinuses and lower stuffiness. Heat on the sinuses helps relieve pain. This can be hot wet compresses, a heat lamp, a 60-watt light bulb, or a heating pad.