Hi Futuremum
Our lab also gets this problem on a fairly regular basis too We used to use the malaseb wash as Christy mentioned but found it didn't do a great deal. We now have an ear cleaner called Epiotic which you can buy from the vet or pet shop. We have found this to work so much better. We clean our boy's ears out once a week when he is better and use baby wipes and cotton buds to clean the outer ear. When he has the infection again we use the Epiotic daily and antibiotics twice daily and we use a cream on his paws too as he scratches and chews himself too.

I hope you find something that works for your pet