I bought an otoscope to help diagnose any potential ear issues in my rabbits, but I would not attempt cleaning them out myself. If they were to have an ear issue, I would assume it's an underlying medical issue for which I (personally) am not trained to treat.
Have you watched your rabbit groom itself? Notice how it cleans its ears. Remember, they live in the wild, too, and certainly don't have humans sticking q-tips in their ears out there
Also, if you have a pair of rabbits, they will probably clean each other's ears out.