Remove Workbook Names

I have sheet 2007 with 365 named ranges. the names are like "_20070225". I use an intersect procedure that converts the range name into "Sunday, February 25" and places it nicely in a label on a user form. To name the ranges on sheet 2007, my procedure used DateSerial (2007,1,1). I named another sheet 2008, changed the naming procedure to use DateSerial (2008,1,1), and while it works, the intersect procedure throws an error for either sheet. I assume it has something to do with hidden names, or the fact that all names for both sheets are in workbook.names.
Here is the intersect procedure that I call from sub Worksheet_SelectionChange(ByVal Target As Range)

Sub cellINBMs()
Dim nName As Name, str As String
str = ""
For Each nName In ActiveWorkbook.Names
If Not Intersect(Selection, Range(nName)) Is Nothing Then
str = str & nName.Name & ";"

End If
Next nName
If Len(str) <= 1 Then
str = ""
Else: str = Left(str, Len(str) - 1)
MANAGERCONTROLSFORM.SELECTEDDAYLABEL.Caption = Format(DateSerial(Mid(str, 2, 4), Mid(str, 6, 2), Right(str, 2)), "dddd, mmmm d")
End If
End Sub