How do I get rid of congestion quickly?

So I get sick often, and most of my sicknesses come with lots of congestion. It takes me a long time for the congestion to go away, even after the other symptoms of the illness have long gone. This is a big problem since I am a singer and being congested makes my singing voice bad. I've been taking decongestants and anti histamines and nasal sprays. They clear my nose enough to be able to breathe okay, but my voice is still very much impared by the congestion that seems to be logded deeper. I need a quick fix to get rid of this problem, since I have upcoming performances.