The Remove method deletes the environment variable specified by strName.
WshEnvironment.Remove(strName)
 ' Delete the EXAMPLE volatile environment variable
  Set WshShell = Wscript.CreateObject("Wscript.Shell")
  WshShell.Environment("VOLATILE").Remove("EXAMPLE")
' Delete multiple variables
  Set WshUsrEnv = Wscript.Environment("User")
  WshUsrEnv.Remove("EXAMPLE_1")
  WshUsrEnv.Remove("EXAMPLE_2")
  WshUsrEnv.Remove("EXAMPLE_3")
  WshUsrEnv.Remove("EXAMPLE_4")