For me “How long could I get away with driving like an ABSOLUTE ASSHOLE all the time before I lost my licence or had an accident.” Speed limits, red lights, stop signs… forget them all. Every day I have to drive sensibly and obey the law because without my licence I dont have a job, and every day I see at least one person driving like an absolute moron and I wonder…
You would need volunteers, but let them witness the experiments that disprove chemtrails or flat earth bullshit themselves and in person allow them to inspect the equipment and so on.
See which ones of them are willing to actually take whats presented to them and see with their own eyes and re-evaluate their position.