Are all eucalyptus oils the same?

No. Although eucalyptus oil can potentially be quite healing to the inflamed mucous membrane, you’ll only realize this benefit if it’s a medicinal eucalyptus. It can be inhaled either with or without steam, although the former method is more effective. I recommend spraying the Sinus Survival  Eucalyptus Oil (highly medicinal) into a steam inhaler several times over the course of 15 to 20 minutes of steaming. Without steam, the eucalyptus can simply be applied to a tissue, which you can then hold in front of your nose while breathing through your nose (if it isn’t too congested) for a few minutes. After an initial cough, this usually feels very soothing to the entire respiratory tract, while very effectively relieving nasal congestion and sinus headaches.
There are approximately 730 different varieties of eucalyptus trees, but only eleven are rated medicinal by the U.S. and British pharmacopeia (drug directory). The Sinus Survival Eucalyptus Oil, which I’ve been recommending for more than fifteen years, is imported from Australia, and is the most-highly rated medicinal eucalyptus I’ve found. I have tried others that are not as effective in treating the symptoms of sinusitis. I’ve also found it to be useful as a nontoxic germicide for cuts, burns, and cold sores, and as an effective topical pain reliever for arthritis and muscle soreness.
You should always have a bottle in your medicine cabinet, car or emergency kit.