I use those brushes that are made of rubber – the ones where the “bristles” are kind of large rubber bristles. I use that, and brush the wrong way first, then the right way to get the fur off. I feel best about that kind of brush because its pretty unlikely to damage their thin skin, and its also fairly easy to clean off.
Also, Beka, I have a sneezy bunny that is quite allergic to changes in his environment as well. When Brian first got him the lady we got him from was like “he’s SNEEZING? o woe he is going to die” and all dramatic, so my poor fiance spent the night extremely upset because he thought he was going to lose his bunny. Well, the bunny is still around and still sneezes a couple times a day, and is perfectly healthy and enjoys harassing me daily with love nips
I think the real sign is the discharge. I fostered two babies that had sneezes with discharge, and that was extremely hard on them. I had to wake up 2-3 times per night when I heard them having a sneezing fit so that I could wipe their noses and help them breathe easier.