A few grains up to a pinch of Cayenne pepper (powdered, the kind you get at the grocery store)in 1/2 cup water, gently snuffed up each nostril, will clear most sinus congestion very quickly and stimulate circulation to those sluggish sinus areas, helping to flush out any impending infection. If you are completely blocked, you can put 1/2 tsp cayenne in 1/2 cup water or juice and drink it down. Yes, it's hot but the heat goes away once circulation is restored. Another method I use is placing the cayenne in the center of my tongue and chasing it with juice...I'm very wimpy and can't handle hot stuff so this is less hot for me.
Also, during illness it is important to help the body eliminate toxins as quickly and easily as possible. Using an enema can help. For all types of congestion a Garlic enema combined with ingesting some form of Garlic is helpful. Te Garlic enema breaks up congestion throughout the body and hlep to eliminate it. The use of Garlic taken orally builds the immune system...it's a blood purified and antibiotic. Use 1 tablespoon garlic per cup of warm water for enema, retain for up to 15 minutes.
Remember to eat raw garlic...cooking destroys the beneficial properties.