I have the following code in a from where user is to enter New Ingredient.  
It catches the error when a duplicate Ingredient ID is used.  It works so
far, but what I want it to do is to clear the incorrect IngredientID they
have started to enter it.  I can't figure out what code to put after the
message box

Private Sub IngredientID_BeforeUpdate(Cancel As Integer)
   Dim varIngredientID As Variant
   Dim strType As String, strWhere As String
   
   strType = Me.IngredientID
   strWhere = "[IngredientID]=""" & strType & """"
   
   If IsNull(DLookup("IngredientID", "dbo_Ingredients", strWhere)) Then
         
   Else
   MsgBox "The Ingredient Code you have entered already exists.  Please use
a Unique Code"
   
   End If
   
End Sub