Cat’s ears are generally self-cleaning. However, if there is excess way or debris, you may need to clean your kitty’s ears. Gather all your supplies together so you can work quickly and efficiently. Determine whether your cat will allow ear cleaning with little or no restraint or whether you will need to wrap her in a towel. Hold the head and use your thumb to turn the earflap open to access the ear canal. Use tweezers to pluck any hair blocking the ear canal. Drip a cat-approved ear cleaning liquid in the ear canal. Close the earflap and massage gently to spread the fluid and loosen debris. Clean away the debris with a clean cotton ball. Use fresh cotton for each ear. You can use a cotton swab but not any further than you can see to avoid causing damage to the eardrum.
Source: Cleaning Your Cat’s Ears