Try the Neti pot or if you don't want to buy a special pot, use a measuring cup with a spout - makes it easier to get the saline solution up your nose. Basically, you're flushing out your sinuses with saline. Do it over a sink or in the shower - it's a messy process!

It helps keep my sinuses clear during the allergy time of the year. I do it regularly anyway as I was having horrible problems with sinus infections. No more infections since using the Neti pot (or method).