Rooibos tea cleared up my sinuses after suffering for 4 years. I got very stuffy from it initially, and almost quit taking it (but wanted to continue for added health benefits), and all of a sudden one day I realized that I it cleared me out. I guess it took about two weeks of taking the Rooibos tea on and off before it cleared me.
Tea for Sinusitis/Sinus Infections
On my tiresome quest to find a cure to end my sinus congestion issues, I discovered that tea is the cure! All sorts of tea have completely cleared up my sinuses - Raspberry tea, Lemon Balm tea, and Hyssop tea are my top contenders for clearing effects. You have to drink A LOT of it - like 4 cups 3-4 times a day! I typically put 4 tea bags in a tall glass and drink all at once, then repeat that 2 or three times. Ideally, you should order the organic version in bulk loose and put 1 or 2 tea balls into a large glass. Let the tea soak for about half an hour so that it's strong. I don't know what it is in tea that has this clearing affect, but it WORKS!!
Quick note: the first couple of days you may go through a detox and feel more congested. Don't worry! That's just detox and the tea (unless of course you are having a real allergic reaction) is just clearing stuff out!