How to use shared material as my material

I am trying to create the prefabs from runtime in script and it seems like each prefab is using each instance of the original prefab and drawcalls become extremely dangerous. I tried to set the shared material as my main material as follow but it doesn't work... How can I setup the material to use it's shared one when doing realtime creation of the prefabs..

• button.renderer.material.CopyPropertiesFromMaterial(button.renderer.sharedMaterial);

• button.renderer.material = button.renderer.sharedMaterial;

They both doesn't work for me.. :(