Natural decongestants have the added advantage of not bestowing unwanted side effects upon you during your time of congested distress. Onions are a natural decongestant, loosening mucus and enhancing easier breathing. "Even the fumes of an onion as you cut it up will help to loosen the mucus and actually eating onion in its raw form will definitely have a positive impact on lessening congestion."
Bell peppers may also help break up congestion.
Steam can be used in a vaporizer or simply with the use of a pot of boiled water and a towel. Just put the towel over your head, and breathe in the steam. Eucalyptus oil can be added to the steaming water for greater benefit.
The use of a neti pot can help to clear sinuses and keep them clear through regular use. If you don't have a neti pot, the basic premise will still hold true. Inhaling saline water (water with salt in it) up into your nose can help relieve congestion.