To this end, I have purchased a nasal irrigator. One adds special salts to water which is then squirted at high pressure up each hooterhole in turn. When the tubes are clear, the water exits via the other nostril, the mouth and the ears. When the nose is blocked... well, don't ask.

Anyway, it's definitely starting to work, but the downside is that sometimes water pools in hidden cavities and then, some time later, one rises from one's desk, or nods one's head, and a pint of water and sinus matter pours out of the nose.

This can be embarrassing. I style it out quite well thogh, I think.