What is the cure for post nasal drip?

Depends on the cause: The worst phrase in medicine is "post nasal drip". I hate it because it implies that what you are feeling has something to do with your nose. Your symptoms of the feeling of abnormal mucous in your throat might be due to your nose and then again might not. In my experience the most common cause is what we eat and drink often associated with reflux leading to throat irritation. See an ENT for exam.

Depends on cause: Post nasal drip is from acid reflux, too dry saliva, retained throat secretions because the pharynx can't clear them, pharyngeal diverticulitis, foreign body sensation from globus, habit, chronic nasopharyngitis, and others. It rarely indicates a serious condition but i would be most concerned if there is coughing or choking with swallowing, hoarseness, or abnormal swallowing. Know cause to treat.