In the last year I have discovered the most powerful de-conversion device for the World: religious unity.
Most religious tend to focus on religious unity between groups of their own faith, but having been exposed to a Church with the aim of uniting all world religions for a year before I de-converted I feel that they really helped me question my own beliefs. I am involved with their peace based organisation, but because I was a practicing Christian they invited me to their religious workshops, where I learned that I did not know much about my own beliefs and began studying the Bible a great deal more in order to be sure that I knew what I was talking about.
The unity of religions will dilute the messages of the past and allow people to adopt a new age of spirituality. The Unification Church itself will (in my opinion) result in a generation of believers who have no affiliation with the bible, and just appreciate all previous world religions. But my hope is that it can play a large part in wiping out at Christianity, Islam, Judaism and all the other harmful religions that make claims of being visited and spoken to by God. I've got no problems with the deists who believe there is a God but don't make up lies about being told by God what to do, because that does not stop their search for truth.
Their teachings have a multitude of arguments against the commonly held beliefs of the bible, and might contain many new ideas for you when attempting to de-convert a Christian. When I attended their workshop I remember being disgusted when they said that Jesus failed, but their argument was pretty strong and judging by the amount of Christians who converted to that church I think it's fair to say that their model also has the power for total de-conversion.
People need to belong to something, we need the comfort of a force greater than ourselves that looks over us, and religion provides that. But the truth is that that is a childhood fantasy, and I suspect it might be holding back the world from much of their personal development. So it might be fair to say that if we want to have any hope of making the world a better place (i.e. without fairy tale religions) we might need to convert them to their own personal process of de-conversion. We might need to provide them with a community to de-convert with. I've actually been spending lots of time with the unification church guys and I feel pretty comfortable with them because apart from their belief of their leader being the messiah, I really love a lot about their movement. I sometimes feel that his alleged encounter with Jesus may have in fact been an encounter with doubt, causing him to realise that since Christianity is false it means that people can follow a lie, allowing him to form an entire religion based on a false premise.
I am fully aware of the Moonie cult, etc. but now I know that Christianity is a cult, I consider the Moonies to be a better version of the cult because this generation of it's followers are much less like religious folk, with most of them attending university, and many of them are in the sciences. Because of this I anticipate the next generation of them will appear more like deists or even spiritual agnostics or mystics.
I can't be too sure where this thought will lead, but the unification movement played a massive role in my de-conversion. I realised for the first time that loving people can be more abundant outside of the church I know. I realised that we ignore a great deal of the bible, only focusing on a small subset of it in our tiny little churches. I realised how little we were allowed to think in my church and how much we were indoctrinated to accept particular interpretations of the bible. And most importantly I realised that, with them being the best shot at uniting Christianity that there was absolutely no unity within the church and also that the bible is exorbitantly ambiguous and flakey. Encountering them caused me to really think about my beliefs and despite the controversy of this topic I really do think there is something that can be learned by that group in some way.