This was given to me many moons ago, not from a quack but a Harley St. Specialist. and works a treat to unblock noses.
Before getting dressed in the morning, heat your face and neck with hot water so that it does feel hot. Then, if you can be brave enough, Splash icy cold water on face neck and specially on your chest, do this for a few splashes until it takes your breath away. You will find that your nose runs after about 5 mins. cheers Penny