For a blocked nose and thick mucus, you can use an over-the-counter decongestant like pseudoephedrine to ease congestion, and an expectorant like guaifenesin to thin the mucus. Using a saline nasal spray or a Neti pot can also help flush out sinuses safely. If you use a decongestant nasal spray (like oxymetazoline), do not use it for more than 3 to 5 days to avoid worsening your symptoms. Drink plenty of water to help thin the secretions. If symptoms persist beyond 10 days, worsen, or if you develop a fever, please consult a healthcare professional for a proper evaluation.