Some of the most popular clean jokes were the one-liners told by comics of the early to mid-20th century, such as Henny Youngman, who said, "When I read about the evils of drinking, I gave up reading," "I just got back from a pleasure trip. I took my mother-in-law to the airport," and "Take my wife. Please!" Other categories of clean jokes are puns, jokes for kids and Christian humor.
Jokes based on puns are sometimes known as "groaners," because the humor, while clean, is often corny as well. The situation in a joke such as, "I went to the doctor and I said to him, 'I'm frightened of lapels.' He said, 'You've got cholera.'" is inoffensive, and exists only to deliver a laugh.
Jokes for kids are, by their nature, clean, and often take the form of riddles. One such joke is, "What's brown and sticky? A stick." Riddles also have the advantage of being easy for children to memorize.
Christian culture frowns on risqué humor or curse words, so jokes with a religious bent tend to be clean enough to be told in church. One example is, "A little boy opened a Bible and a leaf fell out. The boy picked it up and said excitedly, 'Look what I found. It's Adam's suit!'"