I've seen this subject come up rather frequently here on the forum and to now have refrained from getting involved in the conversation for fear of saying something which will offend others. While offending others is certainly not the intent of what I am about to say, here is an alternate view.
Presently, I have rabbits (Dan, Londa, McCool, Chief) who have beaten rather severe cases of the snuffles. Of course, it took a little owner intervention and TLC to turn the trick, but each had advanced cases which involved significant globs of white snot coming from the nose after long sneezing episodes, but all it really took to beat the snuffles was a product I'm sure many of you have heard me mention here before. It's called VetRx, and it is suitable for use on everything from snuffles to mites. All I can tell you is that using it per directions, it WORKS!!!!
I have no vested interest of any kind in promoting this product, but I gladly pass along feedback on it in order to help others. I bought a bottle a few months back at the feed store in which I was already visiting to get rabbit feed, and it set me back to the tune of just under $7 (tax included).
I won't debate with anyone on whether or not advanced cases of the snuffles are "curable", as I'm sure everyone has their own opinions on the matter, but in the above stated cases, I'd submit to each of you that it can indeed be cured. Disagree if you want to, and it won't likely hurt my feelings at all.