A method for separating mixed granular material based upon dissimilar specific gravities, (such as in firearm range cleaning) thereby separating lead from backstop material. Lead falling from an airstream is airwashed by an upwardly directed second airstream. The preferred method is performed under negative pressure to control lead dust. Application to pick up and clean or recover fouled ballast rock (such as used in the rail industry). Processes and apparatus are disclosed that pick up and clean or enrich precious metal bearing ore.