"Hi, we're missionaries from the blah blah blah church."
"Oh, no thank you, good-bye."
"Is there anything we can do for your family today?"
"Um, do you do windows?"
"Oh sure, we would love to do that, really."
"It's okay, I was just joking."
"In that case how about cleaning my toilets?" Is what I should have said and made them do!
And they politely left.