I'd also be interested in techniques for defeating other people's ugh fields. That is:

If someone else (probably not a rationalist) has an instinctive flinch away from an idea, how do you talk to them about it anyway?

At the moment, my best method is to approach the idea from a perspective that makes it not immediately clear that I'm talking about the idea the field surrounds. I really don't like doing this because it fields underhanded, and tends to produce negative reactions (although I've had more success with this than anything else).