200 asf most preferably 40 to about 120 asf e g 50 to 100 asf at higher current densities areas of high current density on the work piece e g edges may become pitted this pitting can be avoided by the use of shields known in the art to protect such high current density areas while any convenient temperature can be used to carry out the stripping operation a suitable operating temperature range is about room temperature i e 70 u00b0 f to about 150 u00b0 f preferably about 100 u00b0 f at the higher temperatures stripping is accomplished at a faster rate however etching of the substrate metal can occur at temperatures significantly above 150 u00b0 f the time to complete the stripping process will depend on the amount of material to be stripped as well as the voltage current density and temperature used in conducting the stripping process generally the stripping operation can be accomplished in about 30 minutes to about 24 hours in carrying out the stripping operation of this invention it is preferred that the soluble iron content of the chromic acid solution be less than 15 grams per liter at higher concentrations ion build up results in higher voltage requirements the advantages of the instant invention may be more readily appreciated by reference to the following examples steel substrates.