If you are not allergic to feathers, a very small, light feather pillow could help, too. I have found that a feather pillow will block out high-pitched sounds (though not bass-pitched sounds). I sleep on my side, so I just plop the small pillow over the ear that's facing up. It blocks out early morning bird sounds on mornings I want to sleep late - and it just might block out cat wails. I can't remember if I have tried it for cats.