Nasal irrigation with saline solution (whether using a neti pot or the squirty bottle "lavage" systems sold by allergists) can do a world of good for people with sinus problems. I've successfully avoided having to take antibiotics for sinus infections by irrigating morning and night with warm salt water.

It's also really nice in springtime when you've been out inhaling pollen all morning, it rinses many allergens out. The alternative is to let your body do it's job and produce copious amounts of mucus to carry all those pollens away, potentially experiencing a lot of histamine-related symptoms in the meantime.