"Escalators donﾒt break down, they just turn into stairs;" I intend to live forever, or die trying;" and "A clear conscience is usually the sign of a bad memory" are all clean one-liner jokes. These jokes are typically suitable for day-to-day conversation with friends or family.
Other clean one-liner jokes include: "Today a man knocked on my door and asked for a small donation toward the local swimming pool. So I gave him a glass of water;" "The only time incorrectly isnﾒt spelled incorrectly is when itﾒs spelled incorrectly;" "I used to be in a band, we were called ﾑlost dog.' You probably saw our posters around;" "'Iﾒm sorry' and 'I apologize' mean the same thing, except when youﾒre at a funeral;" and "Sleep is my drug, my bed is my dealer and my alarm clock is the police."
A string of clever, clean one-liners that can be used in immediate succession is: "Want to hear a pizza joke. Nah, itﾒs too cheesy. What about a construction joke? Oh never mind, Iﾒm still working on that one. Did you hear the one about the rope? Skip it. Have you heard the one about the guy in the wheelchair? Never mind, itﾒs too lame."