If you want to clear all formatting, I'd suggest this:
With Selection
.ClearFormatting
End With
This resets the paragraph style to Normal and resets all fonts and attributes (that I've tried to set). Note that it resets the paragraph style for the paragraph that includes the selection (so if you've only selected a single word in the paragraph, it still resets the style for the paragraph).
ref: MSDN: Selection.ClearFormatting
I didn't see any difference when I added ActiveDocument.CopyStylesFromTemplate NormalTemplate.FullName
but I expect this would depend on the complexities of your documents.