I think that sometimes in the warmer months the smell is more likely to be noticed. I take it the smell is under/just before ear opening.
I have used Thornit powder on both cockers - although I had a cleaner from the vets for my first cocker, next time I asked I was given another type which was hopeless. Thornit powder is a staple cocker owners product.
Does Reese seem to have any discomfort with his ears, like scratching, rubbing side head on floor, this could be an ear infection.
While I have not used, Virbac do an ear cleanser which is just one on the market. Must admit I use Virbac products and they are my first choice.
Julie