You can charge 20% of the value of the item, which the general library will not charge. Obviously there is blackmail, especially for students.

I suggest you give them newspapers as long as they are in your city. This kind of charge is so immoral that they should be stung by 1. Maybe the library leader is afraid of shame and can give it back to you for free.

There is no need to quarrel with the security guard. Anyway, they have your things and dare not take them away or dispose of them easily, because you have asked them to return them. If they are lost, you can ask them for compensation.