Private Function ExtractNums7913(expression As String) As String
Dim a() As Byte
Dim b() As Byte
Dim ct As Long
a = expression
b = a
For x = 0 To UBound(a) Step 2
If a(x) < 58 Then
If a(x) > 47 Then
b(ct + ct) = a(x)
ct = ct + 1
End If
End If
Next
ReDim Preserve b(ct + ct)
ExtractNums7913 = b
End Function