As the question states. I believe a mortar and pestle is more for things like nuts, seeds etc. is that the case or will it easily make fish bones e.g. sprats, sardines into small particles?If there is a specific material of mortar and pestle I need?
Just to add, when answering this question you should imagine the bones are raw or have been boiled for 20 minutes i.e. not fried, pressure cooked or other methods. i know for example fried sardine bones crush easily, but i doubt raw or boiled bones break easily.