Considere o uso de um pequeno U ser D efinado F unção (UDF) :
Public Function LowerKiller(sIn As String) As String
Dim L As Long, LL As Long
Dim sCh As String, temp As String
For L = 1 To Len(sIn)
sCh = Mid(sIn, L, 1)
If sCh Like "[a-z]" Or sCh = " " Then
Else
temp = temp & sCh
End If
Next L
LowerKiller = temp
End Function