If you have heard of a "Neti Pot" the following will be somewhat like that but cheaper and easier to use. I had clients tell me that they do this often (up to daily) and had great results in reducing their sinus infections and seasonal allergy symptoms. I have used this method myself and also have had good results.
Clean your bathroom sink very well. You may also use a bowl instead.
Fill your sink or bowl 3/4 full of warm water.
"Thoughly" mix in the water about one heaping teaspoon of:
Baking soda (See below info on baking soda),
Non-Iodized Salt and two teaspoons of
Put your face in the water and breath in a "small" amount of the water mixture. You will not want to get this in your lungs, just in your sinuses. Repeat this maybe 4 times and you will feel the mixture loosing up gunk you didn't know you had in your sinuses.
Baking soda helps regulate pH—keeping a substance neither too acidic, nor too alkaline. Think of pH as a see-saw, with acidic pH tilting one way, alkaline pH tilting the other way, and neutral pH when the see-saw is level. When baking soda comes in contact with either an acidic or an alkaline substance, it's natural effect is to neutralize that extreme pH - tilting the see- saw back toward level. And beyond that, baking soda has the capability to resist further changes in the pH balance - keep the see-saw level--this is called buffering. This buffering helps prepare the water going into your sinuses to be pH neutral and safer and more therapeutic for your sinuses.
NOTE: It is important that you do not use chlorinated water, instead try using filtered, spring or distilled water.