Fuller Brush is indeed a company, that started out selling home cleaning products, but I believe later included other products as well. They did door-to-door sales (coldcalling) back in the 50s, I think, maybe even earlier?
Anyway, I think it's pretty safe to say that in North America, if you say "Fuller Brush" salesman, a stereotypical image of the old-style salesman knocking on the door in the middle of the day, foot jammed in between so you can't close the door, comes to mind.
(They did not do vacuums)
Jehova Witnesses also come knocking on your door unannounced, often with a baby in a carriage, trying to start up religious discussions and leaving you a copy of the Watch Tower..if you get sucked into a conversation, even to counter anything they might say......they WILL be back.
ps - Fuller Brush no longer does door-to-door AFAIK, Jehovah's Witnesses still do.....