Nasal irrigation is a cleansing technique developed in India. It usually sounds weird to Westerners when they first hear about it, but it's very simple, inexpensive, and effective. Once you try it, it's one you will especially want to do at certain times, such as if you're exposed to dust, or if you're on the backside of a cold or allergies and and have a lot of nasal congestion.
You first obtain a neti pot, which looks like a kind of miniature teapot without a cover. They can be found at some health food stores, Indian markets, and Yoga centers. Add l/4 teaspoon of salt (we prefer sea salt, though regular non-iodized table salt can work too). Then fill the neti pot with lukewarm (body temperature) water and stir to make sure the salt is dissolved. The salt basically makes the solution a germ-killing antiseptic.
1) Standing over the sink, 2) lift the neti pot to your nose, 3) now just gracefully tilt your head to the side, away from the neti pot, keeping the neti pot steady and in the same position. As the pot is raised in this manner, water will simply pour into one nostril and straight out the other nostril. There's nothing forced about this. If you are not standing over the sink, you'll get water all over you as well as down your throat. If you have your head forward, it will go straight through and out the other nostril.
I usually do half a pot in each nostril, going back and forth every little bit from one nostril to the other. You'll find a little residual water in your nostrils and sinuses. Use a tissue to gently blow and remove it. Wipe out your nostrils with a tissue as well. You may have a bit of post-nasal salt water drip, but after a couple of minutes, it's all gone. There's no discomfort involved in any aspect of the process and your sinuses are a great deal clearer afterward than they were before.
If you screw up, so what. It's only warm salt water. Pretend you're at the beach. If you just can't get the hang of it, any yoga center worth its salt will have people who know how who would be glad to show you how. It would take about two minutes.
When you've been sick with a head or chest cold, your mucous contains dead white blood cells and other stuff your body is trying to clear from your lungs. Using the neti pot assists this aspect of your body's natural detoxification process.