Chris: At risk of repeating myself, ionic contamination is almost always a result of a SLOWLY dissolving metal deposit, likely in your case to be imbedded pumice. You need a chemical clean that will dissolve that residue. In your case, you may be lucky, and it may be as simple as a simple acid wash. If that is the case, it could be rapid, and run unheated. If however, the laminate/soldermask has reacted with the metallics, you will need an alkaline, chelated, product, which will take longer, and require a heated solution. A number of vendors supply such chemistry, including us. Contact me directly, if you would like more information, or samples of our magic. Rudy Sedlak RD Chemical Company [log in to unmask] phone 650-962-8004 ################################################################ 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 ################################################################ ################################################################ 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 ################################################################