Beryllium has found applications in the nuclear industry as components in weapons and nuclear reactors, in the aerospace industry for special structural applications and in precision navigational instruments such as gyroscopes, The purity of the beryllium is known to have a large impact on its mechanical and chemical properties, including its corrosion resistance, Although chlorinated solvents have long been used to degrease and clean beryllium parts, not much has been reported about the potential effects of residual cleaning and processing agents left on the surface of beryllium, Recently, samples from some of the beryllium cladding that has been used in the nuclear industry have been found to contain corrosion promoters, e.g. chlorides. In addition, machined surfaces of more recent beryllium metal, e.g. S200 grades, were found to include chlorides, This paper involves using K-ray photoelectron spectroscopy to examine the effects of residual chlorinated solvents on beryllium under near-ambient conditions. Interpretation of the data concludes that these chlorinated solvents react with the beryllium metal surfaces to produce chlorides. Thermodynamic calculations are used to corroborate these results. A mechanism is proposed to explain the loss of the native protective oxide which exposes a reactive surface to the chlorine in the solvents to produce a chloride. Copyright (C) 1999 John Wiley & Sons, Ltd.