The vet, mind you not the regular one that we see but at the same office, mentioned a 50/50 solution of vinegar and alcohol to be dispensed a few drops at a time into each ear periodically. This is supposed to help keep them dry.......if you live in the rainforest like we do here in the Pacific Northwest, keeping a dog's inner ear dry is quite a task.
Maddy runs around like a crazy woman in the rain AND snow and frequently gets moisture in her ears, especially when they flop back from her shenanigans. It never fails how much we dry her or the ears, she's had two yeast infections in that past 3 months or so. STINKY! :o