I read some posts over at Etherbun (a good forum for health issues)
I also got a couple of responses regarding this when I posted your question there.
Recommendation from posters there were not to leave it sitting on the surface. Basically putting it underneath litter or underneath paper. But they also said they didn't have a bunny interested in eating it.
But for me that doesn't mean that if a bunny did find interest in it, or just came in contact with and licked it off their paws that it wouldn't have some negative reaction. I don't know, soooooI am still going to talk to a rabbit savvy vet and get her words on it, and I'll be back with that info.
In the meantime, I learned a new cleaning trick from them!!! Use baking soda with vinegar to help "fizz out the yuck"- as one person put it,