“A Scout is Clean. A Scout keep his body and mind fit and clean. He goes around with those who believe in living by these same ideals. He helps keep his home and community clean.
The simplest way to be clean is not to get dirty in the first place. That goes not just for your clothes and your body. It also goes for your thoughts and words and deeds.
You never need to be ashamed of the dirt that will wash off. If you play hard and work hard you can’t help getting dirty. But when the game is over or the work done, that kind of dirt gives way to soap and water.
But there’s another kind of dirt that won’t come off by washing. It is the kind that enters your mind. An important part of your battle against that kind of dirt is selecting the right friends. Keep away from fellows who seem to get a kick out of swearing and telling dirty stories. Get in with a clean crowd where you will hear clean speech, and find clean sportsmanship, and get a clean outlook on life.”
-William Hillcourt, Boy Scout Handbook, 9th edition