Thank you very much guys, this is great!

I'm just wondering how you created the cleaner box with hole, with the additional 8 loops.. I guess one way is to make a cylinder with 2 cap divisions, delete the faces inside the inner division and extrude the faces out, then manually moving the verts to the grid so that it becomes a hole within a square plane then extruding that to create a solid mesh.

I'm guessing you didn't use that method though, just manual split poly tool, using snaps to the middle of the face edges?