Sorry for the late response! I am glad to see the forums are starting to get some activity, though.
Essential oils that are great for mucus congestion are:
Thyme, Cedarwood, Rosemary, Eucalyptus, Frankincense, Hyssop, and Sandwalwood. Mint and citrus oils would be my second choice.
You can blend your choice of oils and make a “Vicks” Vapor rub. Be sure to use plenty of carrier oil and add to your chest area. You can also make a steam bath, or use aromatherapy for inhalation.