I find that my “No Trespassing” signs work pretty well for keeping the Mormans and Jehova’s Witness folks away from my door.
The Mormons kept coming to my door until I started asking about their having to call their women to heaven and them being "Eternally Pregnant". When I asked about their Elders belief in the "Mother Ship" and the Planet Kobol - they said I really did know something about Mormonism. When they asked if I had read the Book of the Mormon, I said I had (I read it twice) and said that the Bible is far superior to me.
The "Witnesses" stopped coming after I asked why didn't Christ come bodily and Establish a visible world government in 1914? and how were folks bodies preserved since then? (Rather than being Frozen as they want to now).