Well it does say to completely remove the Rain-X . I didn't mean to use an electric buffer. If you can still see a haze on the windshield you need to do some more hand buffing to get it off. A good why to tell is to wipe the wipers once and you will see if it is still on there.
BTW Rain-X now makes a glass wax.
And I have used a clay bar, ammonia, paint remover (toluene), alcohol, acetone and none would take off the hot wax that is used at car washes. The toluene would cut the wax but evaporate before you could get it all off. If you don't think you have wax on your windshield use a bit of the toluene and see for yourself. I will no longer use this and specifically ask that it not be used. If there is no way I can get my car washed without hot wax then it doesn't get washed.