There is no specific law that makes it illegal to bring salt to school. However, schools may have rules and policies regarding the items that students can bring to the premises for various reasons, such as health and safety concerns or to maintain a productive learning environment.
In some cases, schools may restrict the use of salt or other seasonings due to concerns about potential health issues related to excessive sodium intake or allergies. Additionally, schools might want to prevent students from using substances like salt in pranks or other inappropriate activities that could be disruptive or harmful to others.