hello, Blocked sinuses may have multiple causes, but as you mentioned your condition is recurrent, why don t you let nature take it s course to restore health as the body has the ability to heal itself, try these alternate therapies which will aid the body in this healing. Eat pungent herbs like garlic and onion or consume 1 tsp of these extracted juices early in the morning, which tend to break up mucous congestion all through the respiratory tract. Also Take pans of hot and cold water, bathe the whole face with hot water - as hot as you can bear - and then apply cold water for short duration.Nasal inhalation of steam for five minutes every hour will also give relief. As your Phlegm is already green in color it indicates a sign of infection, try these remedies and take care.