You are almost certainly having the soldermask reacting with the alloying parts of your gold, likely the Nickel or Cobalt. You will likely need a good alkaline cleaner to remove these stains. (This is because the soldermask itself will not dissolve in acid cleaners) This is possible, but requires an alkaline cleaner that will not attack the soldermask. This is no small task, but it is possible. If you want specific information, please contact me directly. Rudy Sedlak RD Chemical Company ################################################################ 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 web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################