An orthodox Jewish acquaintance from a long time ago would invite them in with the words 'Welcome, welcome, come in and I'll show you where you went wrong in the translation!'

Usually had them beating a hasty retreat.

One afternoon, again a long time back before I was married, my housemate and I made the mistake of admitting we went to the local church regularly.   They kept coming back, every week for months after that, so one afternoon we sicced a visiting rabid Pentecostal lay preacher on them, and sat there giggling for an hour and a half as they swapped Bible quotes and she got the better of them. They never came back after that.

I usually just say that I'm in the middle of cooking or something (and I usually am) but I'll take the literature and get back to them....

Another friend found a great way to persuade them to leave, the baby was yelling so her being totally unashamed and a militant sort of person, she flopped out a breast and started feeding... they couldn't back up quickly enough - and they were women!

LTS