Dim excel
Set excel = CreateObject("Excel.Application")
excel.ScreenUpdating = False

... [all the codes] ...

' Close the workbooks and exit excel
excel.DisplayAlerts = False
For Each wb In Array(WB1, WB2, WB3, WB4, WB5)
    excel.wb.Saved = True
    excel.wb.Close SaveChanges:=False
Next
excel.ScreenUpdating = True
excel.DisplayAlerts = True
excel.Quit