If you see one of these symptoms, you can examine the inside of your cat's ear for signs of ear mites. The mites themselves are too small for the human eye to actually see without the aid of a special instrument but you can usually see evidence of ear mites if they have established themselves.
What you will see will look like your cat's ear is extra dirty inside. Dark waxy spots. Sometimes you will also see "hairy" material. But basically, look for a grimy dirty appearance.
Some people treat their ear mites at home and if you know your cat is prone to them or another animal in the house has had them before, you may want to go this cheaper route. However, if your cat has never had ear mites before, you may want to take them to the vet because ear infections can be misdiagnosed as ear mites and infections require a different type of medication to treat.
Most over the counter ear mite medications and the medication your vet would give you contains an insecticide called pyrethrin that is usually contained within mineral oil. Before you apply this medication, it is very important to first carefully clean away all the debris in your cat's ear first. If you don't, you will not be successful in getting rid of ear mites.