I tried this remedy (1/4 teaspoon cayenne to 6oz water) and did exactly as it says. My sinuses did drain a little, but my ear continued to hurt and stay clogged for some time. It did drain about 2-3 hours after I went to bed. I have no doubt that it was helpful, but I cannot say I experienced any immediate relief.
I did not have fresh organic cayenne measured by strength; it was Morton's brand and fairly new, but I suspect it wasn't as potent or fresh as could be had.