Private Sub Workbook_Open()
'Reset Right Click Menu
Application.CommandBars("Cell").Reset   

'Create Object reference to right click cell properties menu in excel
    With Application.CommandBars("Cell").Controls
     With .Add
	'Caption for menu
        .Caption = "Convert Values"  
	'Reference to macro that will be called
        .OnAction = ThisWorkbook.Name & "!PasteSpecial"  
        .Tag = "PasteValues"   'Tag reference not needed
        .BeginGroup = True
     End With
End Sub

Sub ConvertVals()
Dim rng_Selection As Range
Set rng_Selection = Selection
For Each Cell In Range(rng_Selection.Address)
    Cell.Value = "'" & Cell.Value
Next
End Sub