I need to write a letter to my principal why you cant bring valuable items like cell phones

and jewellery and reconsider to bring back cell phone and jewellery to school

Our experience with students bringing cell phones and entertainment systems to school has been that too often they go missing (lost or stolen) either in school or on the bus. This creates many issues regarding questioning students and investigating incidents. We feel it is the safest policy for students not to have them in school. As our sites are small, everyone has the ability to make and receive calls to their parents in an emergency. We also feel it can lead to miscommunication if students are being communicated to directly and administration or staff is not also informed.

This should be good