Summarize:

If you have a lot of mucus in your throat, hydration can help. Liquid can help soften mucus, making it easier to expel from the body.  Avoid cold beverages whenever possible. Instead, opt for room temperature water or warm beverages, such as coffee, and tea. Try to drink about eight glasses of water daily. If you're struggling with a sore throat, you may want to increase your water intake slightly. Seltzer water may help with a scratchy throat.  Try to stay away from fruit juices and soda, which are acidic. The added sugar can cause additional throat irritation. If you want something other than water to drink, go for sports drinks or fresh squeezed juices that use only natural sugar.  There is a belief that milk and dairy products increase phlegm production, but there is no scientific evidence that this is true. They may cause the phlegm to be thicker and more irritating to your throat, but frozen dairy products can also be soothing and a good source of calories when you may not be eating because it is difficult to swallow. Honey and lemon both help soothe the throat. Try adding a squeeze of lemon juice and a teaspoon of honey to a glass of ice water or tea. Not only can this help clear phlegm, it may also ease any pain or irritation you are experiencing. Spicy foods can sometimes result in phlegm loosening. This can make it easier to remove via blowing your nose, coughing, and sneezing. Chile, peppers, wasabi, horseradish, and other spicy foods can help clear your throat. Some people find herbal teas help soothe the throat. Try a variety of teas and see if you notice any effect on your throat.  Chamomile, ginger, and lemon teas are most frequently cited as helping with congestion.  Some people find green tea is soothing for your throat. Try adding honey or lemon to green tea for added effect. Certain foods are good for the voice and help promote a clear throat. Whole grains, fruit, and vegetables contain vitamins A, E, and C which help keep the throat free of mucus. If you have a sore or strained throat, try eating softer foods until the irritation clears.
Stay hydrated. Try honey and lemon. Eat spicy foods. Drink herbal teas. Choose healthy foods for your voice.