I thought the clean up would help out here, but if youve messed about with it and cant find it....
What you can do is merge the vertexes, select all the verts in the model and then in the polygons menu find the merge tool and look in the option box, reduce the distance to a really low value like 0.0001 (might have to have a fiddle with it to get the settings right so it either works, which you can check by using the heads up display to see if the vertex count goes down, or it dosent mrege close but not overlapping verts) and then hit merge, this lowers the distance the merge tool works.
I use this method when merging 2 parts of a model thats been mirrored.
"No pressure, no diamonds" Thomas Carlyle