You don't convince the delusional that their delusions aren't real. You ignore them.

Didn't one of those rocket men actually lay down one of the deniers?

Gimmee a minute

Hand them a stupid card.

I don't even try. You can't cure stupidity.

I don't discuss it with them.

You don't.

You don’t. You can’t. Don’t waste your time.

I put them in the same category as climate change deniers and creationists. Ask them for the physics they don’t agree with and ask them to show you the math.

The people who think 9/11 was a conspiracy, same thing. You tell them you saw planes hit buildings, they say: what about building 7, it looked like a controlled demolition job. You go: if they wanted to blow up buildings, why fly planes into them and they always have some other answer. They even say the people in the planes making cell phone calls was all staged. It's lunacy.

Someone approached me on vacation in South Carolina last year and asked "Do you believe story that we went to the moon?". I'm guessing he saw my Illinois plates and was looking for an argument. I explained many things to which he replied with more questions like, "then why haven't we gone back?". I explained that we did did. In fact, we left a perfectly good moon buggy up there. I also explained the enormous cost of going there, and when you learn what you need to know, why go back? He then started speaking about how dumb smart people are. I pretty much gave up at that point.    

    I have met some intelligent people all arouf the U.S. Sadly they're mixed in with all the nuts.

Sic Buzz Aldrin on him!

As with any conspiracy theory, I ask them what the end game is? What is to be gained by faking the moon missions, 9/11 truthers, flat earth, etc.

The I ask if they've heard of Occam's razor... ?

I give up on them.

Look at them. Shake my head as I laugh. Then move on

Ha!
Why would you even try?
Just go along for the ride... see where they take you!

I generally use a baseball bat. But any large piece of wood should do.

I don't waste any time with those who are mentally blind.

Ahhhhh very good question.... you don't go through them, you go around them and then keep on going

You don't, but I ask them if they also believe in an invisible man in the sky.

Footage of man walking on the moon was broadcasted live in 1983.

I don't bother. Actually I enjoy listening to them and the logical gymnastics can be pretty impressive. To explain why the greeks thought the world was round, it is because they didn't understand the higher math that proves it is flat.

You smaile sweetly and turn away.

Waste of time.

You can't. Irrationality is not amenable to reason.