How to delete unwanted material? How to delete unwanted material and texture used in my scene?

I have an interior scene and when I press shift+Z it renders in a good way, but when I press F12 a small render shows up and it's stuck there. I thought of removing the extra material and texture used. Some are assigned and some are not assigned. 

I want to delete all the material and texture which are not in use. I have used the Orphan addon, but did not see any success. Is there any other addon or a quick way to delete them?
In Blender Version 2.79b go to "Blender File" in the Outliner. Find the material you want to remove and right click it. An option to delete it will be presented to you. 

Be warned that this will permanently delete the material with no undo.