My young Brittany has the inner part of his ears getting dirty quite easily.
It is not smelling badly and there is no pus. So I think they just need routine care.
When should I decide that they need to be cleaned? What is the correct way to clean them?
I fear that if done incorrectly it could "push stuff further inside" and that could lead to infection...
There are (in the US anyway) several ear cleaning solutions available at most (all?) pet supply stores.
It is a liquid in a bottle, the label directions generally include putting some amount of the fluid in the dogs ear, rubbing the base of the ear, and allowing the dog to shake out any residue.
I always keep this in my rabbit grooming/first aid kit.
As mentioned in comments "you should never, ever, put a swab or other cleaning tool into the ear canal of" any pet.
As someone else already said, there are some products you can use in liquid bottles. Although my vet said I shouldn't put the liquid inside my dogs ears and use a cotton to clean it up, instead soak one gauze dressing with the liquid, and with one finger put it inside my dog's ears and clean it up, you will feel how deep you can go. If the gauze dressing becomes black after you've cleaned you should look for a vet, it could be an ear infection.
