You just need this:
Okay, so I know what you're thinking: "Her teapot is so fancy! I want to irrigate my nasal cavities AND be cost-effective." Or maybe you're actually just thinking that it looks gross.
In which case you're right. It does. But that's just a minor detail. If you can get past the Gross Factor, you might just find that you really like this. I did. (That's right; I've done this before).
Nasal irrigation originated in an Ancient Hindu medical practice called Ayurveda. It is very old and just as intuitive. Basically, you just pour water in one nostril and out the other. There are a few key details though:
1) The water must have the proper salinity (oh yes, you didn't think this one wasn't going to be about salt, did you?). The salt helps to match the salinity of, well, snot, so it doesn't hurt when the water goes in your nose. You can purchase pre-measured salt mixtures at a pharmacy or health store, or you can prepare your own mixture at home. A good recipe is one pint warm water, one teaspoon canning/pickling salt (more on this in a bit), and one teaspoon baking powder (to cut the acidity of the salt). If you'd like, you can store this solution for up to a week.
2) Make sure to use canning or pickling salt, as opposed to regular table salt, because table salt is iodized and contains other additives that are abrasive to the nasal membrane.
3) Use warm water, as it is more comfortable than cold or hot water.
4) When pouring the solution in your nostril, tilt your head slightly, making sure that your sinuses are higher than your throat. If you tilt at too sharp an angle, the water could go down your throat instead of out your other nostril. This isn't a bad thing, but it's a little gross if you think about it (not that you don't already swallow like a quart of snot a day, or some other ridiculous amount).
The sinus rinse family!
As gross as it is, nasal irrigation is very effective at easing colds, sinus infections, or any other such ailments. More than just clearing out the nasal cavities, sinus rinses also help kill bacteria. The first couple times I tried it, I was, not surprisingly, grossed out. But I've since come to really appreciate its effectiveness. And a little ickiness is a fair price to get rid of a headache.