My dad wouldn't let them in but he was a practicing minister at the time.
He'd answer the door, dressed normally, and say "Excuse me, I'm not fully dressed" then he'd get his white stiff collar (commonly known as a dog collar) and come back with it on. They'd usually freak out and leave

My uncle did that when he was younger. he lived together with my dad,
and used to talk with them for a bit, so one day they came by with a bible for him, but unfortunately he wasn't home, but my dad was, so he asked them to give the bible, afterwards he immediately ran out and threw it on the lawn, to move it over with the lawnmower.

Thats more of a dick move than anything, and he accomplished nothing by doing that