I just don't answer the door! I pretty much do not answer the door unless I recognize the person through the peep hole!
Years ago when I was in property management though, we had this problem at our apartments. All the "no solicitor" signs were posted and they didn't care and we would get call after call from residents.
So I always had to hop on my golf cart and go and argue with them how this indeed was soliciting and it usually ended with me saying we will let the police escort you off and decide if it's soliciting or not!
