When your whole head seems clogged with gunk it seems as though you can't smell anything — except, perhaps, those objects that have very strong odors, like the fresh, clean wafting of lemon. Lemon doesn't just offer an uplifting vibrant odor, it's also a natural expectorant, so it can help in thinning the body's mucus.
You can combine lemon juice with honey to make a tasty drink that helps rid the respiratory system of bacteria and mucus [source: National Health Service]. Honey, in addition to being sweet and delicious, is recognized as an anti-bacterial substance and has been used to combat illnesses for thousands of years [source: Health].
Make a cup of lemon tea by grating 1 teaspoon lemon rind and adding it to 1 cup boiling water. Steep for 5 minutes. Or, you can boil a lemon wedge. Strain into a cup and drink. Or, just add the lemon wedge to a cup of hot tea. For a sore throat that comes from coughing, add 1 teaspoon lemon juice to 1 cup warm water and gargle. This helps bring up phlegm.