In my case, my voice is my primary instrument. Many, many years ago, while working for a local radio station as a newscaster, I had to provide a 5-minute newscast every 30 minutes. Back then we did very few taped cuts and most everything was what was referred to as "Rip & Read", which meant you pulled yellow news sheets from the Teletype machine and read the information live.
Once in a while, when you had a severe cold and sore throat, you still had to provide that 5 minute broadcast until you could find someone else to sit in. The solution was simple. A veteran newscaster said "Just eat a sour onion or dill pickle a minute or two before going on the air and you'll be good for 15 to 20 minutes." He was right. The vinegar used in pickling was a great anesthetic for the throat, cut the mucus and washed it away and for the next 20 minutes I had my normal voice back.
I've only had to do this as a singer a few times, but it definitely works for me. Give it a try--you have nothing to loose.
Good Luck,
Gary