What should one do if they find a shekel at their school?

Found money must be announced for a year if it is of significant value. It is permissible to take a small amount that has no great value and whose owner would not pursue it, without announcing it. The difference between "significant" and "small" is determined by custom and the common practice of people in the locality. The amount is considered to determine whether it must be announced or if it may be taken and utilized.