I've found a miracle cure for spring allergies. A Sinus Rinse, also known as squirting warm salt water up your nose. It is, quite frankly, disgusting. But it works.
Very simple idea. You get about 8 ounces of warm salt water. Warm water, preferably previously boiled, and definitely not cold or hot (it's going inside your head). Then you dissolve a magic salt packet in it, a balance of NaCl and NaHCO3 that makes the water have roughly the same salt concentrations as the inside of your sinuses.
Then you fill the little squeeze bottle, stick it up one nostril, tilt your head forward, and squeeze the water in. Hopefully the water splutters out the other side, or a bit down the back of your throat. It feels a bit like getting hit by an ocean wave and drowning. Messy business that requires a sink, although I manage to keep my shirt dry.
Like I said, it's disgusting, but it seems to really work for my pollen allergies. I guess I'm flushing irritants out of my sinuses. A quick rinse after coming in from an outdoor walk and I'm much better off the rest of the day and night.
It's simple enough you can probably make the stuff at home. But for $10 at your pharmacy you can buy a Neilmed kit with bottle and a zillion premeasured salt packets. Your hippie friends may also suggest a Neti Pot, which is a similar idea, but I'm told the positive pressure of the squeeze bottle is more thorough than just gravity flow.