I sympathise that they are currently in a period in their life where they are doing door-to-door sales for a wage.

It’s easy.

1. Deny
2. Take control
3. Show empathy
4. Start their departure.
5. Make them glad they’re leaving

Cut them off, “Oh, sorry. I’m not interested in that. I need to quickly get back to what I was doing. But you have a good day and try stay cool/warm/dry/etc. out there.” Start stepping back, “And be careful of the dog four doors down, it’s a fucking cunt.”

As you close the door, say “You too, bud.” regardless of what they say, even if they say nothing.

They will never return or pursue, and you won’t feel rude.