I travel with Doc's Pro Plugs, vented and leashed, and Ear Shield. Just buy the Ear Shield. It lasts a long time, both in shelf life and the number of times it's used before needing replaced. It is well worth the $20 or so and not worth the trouble of a homemade recipe, IMO. You'll also have to design an actuator that fits into your ear canal to deliver the spray along with a pump to spray it.