This doesn't work that well. Conspiracists won't change their mind despite any evidence. Unless you're a very good speaker, trying to argue with them will only

This doesn't work that well. Conspiracists won't change their mind despite any evidence. Unless you're a very good speaker, trying to argue with them will only give them a "stage" to profess their ideas. Arguing against an irrational but skilled speaker will only benefit the unreasonable one, specially if you arguments are simple and technical: most people don't understand simplicity or technicalities; but get hypnotized by voice, fear, indignation and a feeling of "if he is that person is right them I'm screwed!" The best way to counter conspiracists is (I think) leaving them alone and spread rationality among the ones who are still not sick or can be cured.