Keep the kids out

A man dressed in a suit comes up to the front porch of house juggling a clipboard, some papers, and a briefcase. He knocks on the door and it's answered by a middle-aged man, "Mornin' stranger, what can I do for ya?".

"Well sir, I represent Schneller, Barnum, and Holtz. We're paid by private companies to canvas thousands of consumers like yourself for feedback on their products. Today we're soliciting comments on Vaseline petroleum jelly. Would you have time to answer just a couple of questions?"

"I don't see how a couple of questions could hurt, fire away young man", says the homeowner.

Looking down at his clipboard, the survey-taker asks, "Okay...first, you do use Vaseline, correct?"

"Yessir, for as long as I can remember".

"Great, now what exactly do you use it for?" replies the survey-taker with his pen poised over his clipboard, ready to record the answer.

"Let's see.....we use it for dry skin, chapped lips, and sex."

The well-dressed man stops writing abruptly. He looks around, leans forward and in a low voice says "We pride ourselves in being very thorough sir. I know how you'd use Vaseline for dry skin and chapped lips. But would you mind telling me how you use it for sex?"

"No problem," the homeowner says in a whisper, "we put it on our bedroom doorknob".

The survey-taker gets a strange look on his face and takes a step backwards before the homeowner continues, "It keeps the kids out".