Remplacer les cellules jaunes par une valeur

 For Each c In [A1:D20]
   If c.Interior.ColorIndex = [H1].Interior.ColorIndex Then c.Value = "O"
  Next c

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim c As Range
   For Each c In Selection
   If c.Interior.ColorIndex = [COLOR="Red"]6[/COLOR] Then c.Value = "O" [COLOR="Green"]'6=Jaune[/COLOR]
  Next c
End Sub

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim c As Range
For Each c In Selection
   If c.Interior.ColorIndex = 6 Then
   With c
   .Value = "O"
   .Interior.ColorIndex = xlNone [COLOR="Green"]'Enlève la couleur[/COLOR]   End With
   End If
  Next c
End Sub