Charmion, a good way of shifting a recurring sinus infection that isn't bad enough for antibiotics is NeilMed (not sure about the studylycaps, maybe it's Neilmed). This is a squashy plastic bottle and a collection of sachets of saline powder. You fill the bottle with warm water up to the mark indicated, pour in a sachet of saline powder and give it a shake with your thumb over the hole in the top, then you squirt the warm water into each nostril alternately. It just washes out the sinuses and the saline shrinks back the mucous membranes.
Very relieving, and better than most of the spray bottles because it's warm, and because there's more of it. You have to keep doing it every day - part of the morning routine preferably, because if you do it at night, the remaining liquid drools out onto the pillow. If you do it for long enough - nearly a month, usually - the sinus demon says "Curses, this is too rainy for me" and gets out. It's a big help at hayfever time.
Another help at hayfever time is to find the most local honey you can get, and take a teaspoon of it every day. Local is best, they say, because the local bees will have fed on the weeds whose pollen your sinus demon loves, and by some magic of transference, eating the honey nourished on these weeds helps to quieten down the allergies.