VBA Script for removing alpha characters from a string of alphanumeric text

Sub RemoveAlphas()

' Remove alpha characters from a string
    Dim intI As Integer
    Dim strNotNum As String , strTemp As String
        Set rngRR = Selection.SpecialCells(xlCellTypeConstants, _
        xlTextValues)
    For Each rngR In rngRR
        strTemp = ""
        For intI = 1 To Len(rngR.Value)
        If Mid(rngR.Value, intI, 1) Like "[0-9]" Then
        strNotNum = Mid(rngR.Value, intI, 1)
        Else: strNotNum = " "
        End If
        strTemp = strTemp & strNotNum
        Next intI
        rngR.Value = strTemp
        Next rngR

End Sub