Is it permissible to throw sunflower and pumpkin seeds and chewing gum in the trash to prevent students from eating them in class, taking into consideration that they are food and might be considered a waste of others' property?

If the ta'zeer (discretionary punishment) involves confiscating something of value, then the confiscated item must be placed in the public interest of the Muslims, such as giving it to the poor and needy, or feeding it to animals. It is not permissible for teachers to benefit from it, nor should it be wasted. However, if it cannot be utilized, then it is permissible to dispose of it.