I started using a neti pot or sinus irrigator in college while I was dealing with chronic sinus issues (turns out it was probably from a mold allergy but anyways...). It takes a little getting used to but is 100% safe, all you do is basically squirt saline water up one nostril and everything comes out the other side, then blow your nose and repeat on the other side. It's totally gross, it's totally weird the first little while you do it, and if you're really clogged up sometimes it doesn't even come out the other nostril but out your mouth instead. But I promise you feel so much better after you do the irrigation.
The netipot is good for folks who don't have deviated septum issues; if you do however, you may want to talk to your doctor. I was one of those unfortunate souls that tried it and ended up with multiple Eustachian tube infections because the neti pot drained there instead of out the other side. My doctor told me to stop using it, immediately after the 3rd ear infection. I never had an ear infection before or after that experience.