To Mr. Jay Stuart
I haven't found any publication in common scientific literature about use of sodium sulphide for exposure of lead residues in common scientific literature. There are some articles in special editions on forensic methods, wrritten in Russian language, but I haven't originals in my posession, only references in official procedure guide (because that articles were issued long time ago -- 1960s -- 1970s). So, all I can is to give details about chemical reactions taking place. Sorry