Sub Kleanup()
    Dim A As Range, aa As Range, L As Long, i As Long
    Dim CH As String, temp As String
    Set A = Range("A:A")
    For Each aa In Intersect(A, ActiveSheet.UsedRange)
        If aa <> "" Then
            L = Len(aa)
            temp = ""
            For i = 1 To L
                CH = Mid(aa, i, 1)
                If CH Like "[A-Za-z0-9]" Then
                    temp = temp & CH
                End If
            Next i
            aa.Value = temp
        End If
    Next aa
End Sub