The proper way to deal with them must be congruent with the purpose you have to join the skeptic forum. But if the purpose is to "convert" them...
Skeptical people are just people, just like you, trying to organize theirs perceptions about the world, making a meaning and a sense of this just like you, but with other references.
IMHO, avoiding an approach like "I know/ understand something that you don´t" is the best way to connect, share and learn
