Impoliteness expression of teens, such as bullying, speaking rudely, and swearing still happened in school. This article exposed the process of building teens politeness through keroncong. By using project based research, such activities was designed, implemented and evaluated. There are 10 instructors and 50 teens participated in this project. Collaborative activities with keroncong musician, language lecturer, arranger, music lecturer, music publisher, and media partner were designed to increase teen's interest. The results showed that teens can write polites keroncong song if they get challenge, chance, and supporting systems. This electronic document is a "live" template and already defines the components of your paper [title, text, heads, etc.] in its style sheet.