This Guide describes the most commonly used fi eld methods for the retrieval and analysis of soluble salts on steel and other nonporous substrates. Laboratory methods are only included for situations where laboratory control is desired. Much of this information was contained in SSPC-TU 4@ Field Methods for the Retrieval and Analysis of Soluble Salts on Substrates@ which will be withdrawn after publication of this Guide.1 1 Single copies of withdrawn standards may be obtained from SSPC upon request.