Engaging conspracy theories, trying to debunk them ... is always a dual edged sword. On the one hand, bringing sound arguments may convince the undecided to not believe in them, but on the other someone firmly rooted in those beliefs will only see their beliefs validated.
Cnspiracy theories aren't math, so giving a counter example doesn't invalidate them, and using a scientific method doesn't work either, as those people aren't based on a firm scientific understanding.