D.W.
Hello!
If medication is not allowed (or even if it were), the neti pot should help. It is very easy to rinse through the sinuses and helps a lot! Sprouts has them for $15 or so, last I looked. Tip: If one side is completly clogged up, do not use and wait until you can breathe on both sides clearly : ) Regular, non-iodized salt works fine, though the stores also have special salts, if you want to try those.
All the best!