Hi technetters, I have some 24K gold foil that is 16 mils thick that I would like to get very clean and polished for some soldering studies. I have two issues: (1) I have some Au foil pieces that were conventionally polished which have silicon carbide grit embedded in them that I would like to dissolve away. (2) These samples were also chemically polished with an etchant composed of 10% potassium cyanide (KCN) and 10% Ammonium persulfate in water. I was wondering if this solution would leave any residues on the surface....Would a 50% hydrochloric acid, 50% Nitric Acid (aquaregia) etch be better? Thanks for any help.... Steph ********************************************************* Stephan Meschter [log in to unmask] Lockheed Martin Control Systems Phone :(607)770-2332 600 Main Street, MD R52F FAX :(607)770-2056 Johnson City, NY 13790-1888 MARCALL: 8 * 255-2332 ********************************************************* ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################