I have long had problems with my sinuses. When compounded with a cold or an allergy flare-up, it can be real misery.
One of the best treatments is a simple nasal lavage: put a little salt and baking soda in a cup of warm water, then snort it up. I know it sounds repulsive, but it works great. No medicine I've ever taken works as well.
I usually keep a small film can of salt and baking soda in the bathroom, and I take it with me when I travel. Today I realized if airport security ever stopped me and asked me what that suspicious white powder in the film can is, I could reply, "Oh, that. That's just for my nose."