You don’t. They can’t see reason.

I don't think there is a polite way to tell them. It's a blunt comment.

tell them you firmly believe in the tooth fairy

I don't bother anymore. It's like talking to gun nuts, whom I have stopped responding to on this site. Same mind set, different subject.

Do you have the same urge to denounce the beliefs of someone Hindu, Buddhist, or Muslim?
If it's rude to attack people's beliefs for one religion, it's rude for the rest as well.

I don't think there is a way to do so politely.

How important is being polite?

Pointing at them with one hand while using the other to make a circular motion with your index finger pointed at your ear and chanting: "Koo-koo! Kook-koo!"?

Street Epistemology, let them discover it for themselves.

You can't.

I stay away from them!

You don't.

When believers get pushy, I usually say, "I don't insist that you STOP believing; why do you insist that I do?"

It's annoying for others to tell you how to live your life -- either way.

Carefully

Yeah, you don't. You just avoid them or in the event that you can have a real conversation, there is no single line of reason likely to prove monumental, just as there is no one line of religious speak that would send your world crashing down. I get the sentiment though.

If they are a pain in your arse, then just say what you hold to be the truth. But you did ask for polite???

The polite thing to do is not ask them at all ,just as I do not want people asking me why I lack belief.Engaging in conversation with believers in regards to their belief is fruitless and frustrating ,just let sleeping dogs lie.

What is the point in doing so .I could care less if people believe in fairy tales.Let them wallow in their delusions.

Why bother, everyone has the right to his or her own beliefs just as you do. If they realize the fallacy of their beliefs on their own, than good for them. I respect everyone's right to believe, or not to believe in anything that they choose. I just do not want them to try to force their beliefs onto me, and I do not force mine onto them.

I will get back to you on that.

Use a big shit-eating grin like a politician.

I don't see that this really matters since they don't have a polite way to tell someone they're going to hell.

You don't even try, unless they are trying to press it on you. If they are, then it is best to merely explain why you don't believe. Such an approach can be effective in getting them to think, maybe even question their own ideas, but it usually is not and only serves to either encourage them in their conversion attempt or send them away, shaking their heads and muttering to themselves.

Just read the scriptures to them about the talking donkey without letting them know what book you are reading from, then ask them if it sounds like fact or fiction? Most know about the talking serpent in the book of Geneis; fewer know about the talking ass in Numbers.

I don't. I smile and nod when they try to explain their beliefs. To each their own, no matter how ridiculous.

Tell thethat written proof is not enough you want to see the video. LOL