[Sparker]

Natural remedies are acceptable in mild case of URI but the longer you wait to use the real medicine, the greater the risk that pulmonary abscesses will grow and kill your rat.
When rats have a myco flare up which turns into pneumonia, pulmonary abscesses is what eventually takes over the lungs.

If your rat faired well with the natural remedies, I'd say it was probably nasal congestion.

It would be a huge disservice to all the rats if everyone decided to start self treating their sick rats. Rats need vets. Perhaps discuss it with your vet.

*Standing ovation*

At the hospital where I work, our biggest cases are often because of what you just said. Something simple gets out of hand because it was never properly treated.

That said, I use home remedies and whatnot for my pets on a fairly regular basis, but always with a doctor's supervision.