I recently had a student with an emergency situation: she woke up with no voice! This is a little girl (11) who might as well have been born on the stage — she sings all the time! And she had several performances coming up (thankfully she was not the lead in all of them). I frantically asked my colleagues for what would help and several of them recommended SOVT exercises. I had no idea what they were, but one of the kind vocal teachers did a video chat to show me her exercises. I will explain her exercise below, but please check out this website for further information on SOVT exercises. Even Renee Fleming says it changed her voice! (When I find a good article about her comments I will share.)
Essentially, SOVT is singing with a more closed mouth on an “oo” sound to reduce unnecessary pressure on the vocal cords. My colleague recommended getting either a hot cup of water or a steamer, then inhale the steam through the straw slowly. The steam actually touches your vocal cords, unlike simply drinking a warm drink, and is better able to clear out the vocal folds. After that, hum a comfortable pitch through the straw, imagining your voice goes to the end of the straw. Do this only up and down by a few half notes, on a sustained note each time (if the voice is fatigued).
I hope this will help you and excite you as much as it does me! I haven’t finished reading the article yet (have to go teach in about ten minutes!) but it seems like a useful tool for all singers!