With door knockers I very politely ask for their name and what church they are with, once I have that information I more firmly but still polite tell them to leave and never come back. I used to have a list by my door so I could keep track of repeat offenders, if the same church keeps coming back that's harassment but I've only had to get mean once or twice now a days they just stay away.
Out on the street it's usually just someone passing out flyers if I know what they are about I just give a "no thanks" and keep on keeping on.

I suppose what really prompted the question was several ‘interactions’ I had with small groups of vegans. Where I live, a large percentage of the population is veggie or vegan, way above national percentages.
I had a little pocket money job (I’m retired from the corporate greasy pole) three mornings a week, delivering meat from a local butcher to private and commercial customers. I did it to get out, and for the massive discount I got on very high quality and expensive free-range meat and poultry.
On a few occasions, I was accosted by one of these groups who proceeded to harangue me in very loud voices about what an evil bastard I was, calling me a murderer etc. I just went about my business, ignoring them, whilst telling them what they could do with themselves in pure, robust Anglo-Saxon.
One time, I got back to my van, and one of the guys started preaching loudly in my face, and tried to prevent me from opening the van. I attempted to bodily push past him, and he made a grave error - he laid hands on me.
I grabbed him by the throat and threw him against a wall (I’m quite well built). The two with him were quite stunned! As was he.
I opened the van, hoicked a side of lamb over my shoulder and carried on. One of them called back to me and between expletives asked me what poor murdered creature I had. I glanced back and shouted ‘the last fucking vegan who annoyed me’. They were gone when I got back.
I must say I have no problem with veggies and vegans. I know many, and they’re just peeps like every one of us. But I have everything against anyone who attempts to preach at me, and will display extreme prejudice against anyone who touches me (uninvited that is).

Apart from door-knocking JWs and Mormons I haven't really had to experience this. And those are easily dispensed with a "not interested" and closing the door. In theory I suppose there might come a day when I'm playful or peevish enough to want to engage with them, but in practice I have never felt they are worth even rebutting.

It's been a while. Last time, I held on to a barking dog (friendly, but they didn't know) and told them I wasn't interested and to leave. They left pretty quickly, and I didn't have to let go of the dog to beat them with her tail.

Usually "Fuck off with that shit"
And off they fuck.

Why you letting it get ya down? It's not their box.

I can’t even think of the last time I’v been proselytized to. Maybe 2009ish when a good friend asked me if I believed in god when he knew I didn’t. Does that count?