Yeah, but script is easier/faster. Select all the meshes, go to the Utility panel, click the More... button, choose UVW Remove and click OK, then click Materials.
It was a two lines script, but if you like: for theItem in Geometry do ( theItem.material = undefined ) EDIT: If you want it as a command you can associate to a shortcut or a toolbar button, evaluate following code, then go to Customize user interface and find it under Category "Material Tools". macroScript…