uniquement alphanumerique!

Function AlphaNum(chaine)
  temp = ""
  For i = 1 To Len(chaine)
    c = Mid(chaine, i, 1)
    If c >= "0" And c <= "9" Or c >= "A" And c <= "Z" Or c >= "a" And c <= "z" Then
      temp = temp & c
    End If
  Next i
  AlphaNum = temp
End Function

Sub test_i()
Dim a$, b$, i%, j%
Application.ScreenUpdating = False
For j = [A65536].End(xlUp).Row To 1 Step -1
a$ = Cells(j, 1).Text
For i = 1 To Len(a$)
b$ = Mid(a$, i, 1)
If b$ Like "[A-Z,a-z,0-9]" Then
Cells(j, 2).Value = Cells(j, 2).Value & b$
End If
Next i
Next j
Application.ScreenUpdating = True
End Sub