For years I have tried vinegar, soap and other trials to clean the deposits inside old mouthpieces. Today while cleaning some ligatures, I dropped an old soprano mouthpiece into the pan of Tarn-X which is the stuff sold in stores to dip silverware in. I took a toothbrush and rubbed the old white junk off the inside of the chamber. So for this is the best thing I have found. It didn't change the color of the mouthpiece either. I would suggest trying it on an old junker first.