Extensive analytical characterization indicates that the most significant contaminant following dry processing of As-implanted photoresist is not a carbon-based residue, but is in fact arsenic itself. The arsenic residue is an amorphous form of elemental arsenic, relatively free of oxygen or carbon, that is stable for long periods of time. Since arsenic is not particularly soluble in sulfuric acid, hydrogen peroxide, or their mixtures, it makes sense to pose questions regarding the optimum choice for post-dry processing wet chemical cleans.