Public talks: "lose" the outlines you no longer feel comfortable with and choose ones that emphasize Christian qualities or similar. Skip over any points you don't agree with (or maybe over-highlight them so the public may perk up their ears and say "they believe that???")
Bible Highlights: Highlights God's qualities, fruits of the spirit, christian living. Leave out stuff you don't agree with
Service Meeting Parts: If you get a subject you can't stomach, trade in advance.
Congregation Bible Study / Watchtower Study: Concentrate on the scriptures and bring out the context of scriptures, you can always gloss over certain paragraphs in the interest of time, or emphasize them hoping someone catches on to the absurdity.
If the subject matter does not really allow for circumventing what you disagree with, use phrases like "the Watchtower states...", "the book '------' states...", "the Governing Body teaches...", "the outline/paragraph says..." etc.
Sometimes just let the scriptures do the talking. Once I was discussing and article on "house-to-house" preaching and Luke 10:5 was referenced. To put things in context I had Luke 10:1, 5-7 read, which states at the end "Do not be transferring from house to house", I did not comment on this at all, but from the expression on one person's face, it was clear that they had never seen this scripture before in this context and will hopefully make them think.