Although your rabbits will clean out their own ears a majority of the time, you should still check them regularly to make sure that there are no medical problems or material build-ups occuring there. Frequently examining your rabbit's ears will help you spot a number of problems early on, such as ear mites or infections. There should be absolutely no discharge from the ears, excessive wax or brown material in there, as these symptoms indicate health problems (see our Rabbit Illnesses pages).
This Lop-eared Blue rabbit needs to keep its ears clean
If your rabbits are just a little dirty, rather than having an underlying health problem, then you can simply clean the outside of your pet’s ears with a damp rag. Moisten the rag with lukewarm water, making sure that it’s only slightly damp and not wet. When it makes contact with your rabbit's ear, be sure that no water streams off of it as this could make it’s way into the ear canal, causing problems.
Once the rag is moist, gently wipe off the dirt and lightly pat it dry with another rag or a kitchen towel.