If you are squeamish, please don't read mine...
Nasal lavage:
Make a saline solution in the proportion of 1/8 tsp. salt to 1/4 cup water and heat the water so that it is warm to your touch (as milk for a baby's bottle). Don't forget the salt or this will hurt. Pour some water into your cupped hand and gently inhale it on one side. Tilt your head back and let the water go deeper.
Be very careful not to choke if all the congestion decides to loosen at once.
You may have to repeat several times until you are clear.
I read this in either Prevention magazine, ALA or LungLine literature over 20 years ago & it has always worked well for me.