I think I started this...
A polite "I'm not interested thank you" usually does work. My beef, be it religion, vacuum cleaner salesman, or one of the 8000 charity workers, is that if you come to my time, a "no thank you" shall be deemed adequate dismissal as I did not invite you. Any further attempt on the part of the visitor will be met by less than gracious conduct on my part.
Lately the charities have been the worse. I have chosen to limit my donations to 4 charities. I say no to the others, and they start with, "don't you care about...??"
I got caught in the Denver airport a few months ago. I noticed a fellow perched beside a statue, in almost the same position, and laughingly told him that if he held his hand like so, they'd be a matched set. He asked me if I was flying and handed me a booklet about how that was a really bad idea, and a Watchtower. I handed it back, but wasn't quite in the same spirit I had been in.
Joe, can you identity a 30 gauge by the barrel? In my younger years, I worked for Surface Rights one summer. My job was to assess environmental damage done to farmland by oil companies. (In Alberta, a farmer owns the top 6 inches of the land only.) I stopped by one farm that I hadn't phoned ahead of time and was met by a shotgun at the door. It was homecountry so I quickly spurted out, "I'm (my dad)'s daughter! He put the gun down and apologized profusely, and insisted I stay for breakfast. That's not the best way to start a day, a heavy breakfast and all!