Abstract: The invention relates to a method and apparatus for applying a protective film of, for example, oil to the interior of a metal pipe for preservation purposes. The method is according to the invention characterized by the steps of placing one end of the pipe to be preserved against a pipe member provided with a spray nozzle, siphoning over a particular amount of oil from a storage vessel into a bent pipe section of said pipe member, and generating and leading a compressed air pulse through the pipe member and the pipe to be preserved by quickly opening and closing a valve which is disposed in said pipe member between said bent pipe section and a pressure vessel which is connected to the other end of said pipe member.